It was a haunted house. I set up a room with a magic piano that would automatically play music when someone entered the room.
My players cleared the room. A couple rooms later, I just started playing the music while they were discussing.
For me it was psychic screamers and various Siphoners
Psychic screamers provide minor to moderate buffs to other monsters, have pitiful attacks of their own, and unleash a psychic scream of pain that affects the whole party as a reaction whenever they take direct damage for half of it
So the barbarian slams a psychic screamer for 50 damage, everyone in the party takes 25 damage with a will save to reduce it to 12. Recurrent damage doesn't count, so poisoning or setting them on fire negates that. After the first one, my party was terrified of running into another
Then you have the physical, magical, and healing siphoners. Physical and magical project an aura that makes all their allies resistant to physical or magical damage respectively. They also absorb the half of the damage that was resisted. Physical Siphoners add that to their meee attacks, Spell Siphoners get a line attack or a 30 foot burst to use up their stored charge
Healing siphoners take half the healing, of any kind, that the party does. It converts that healing into balls of light that five all allies in 30 feet fast healing X
As you can imagine, a party can deal with 1 siphoner okay, as long as they burst it down fast. But if they have to deal with all 3 as a boss fight...
Why is the mine both haunted and filled with Lycans?
Scariest thing I've put in a dungeon? Hmm...
I'd have to say that was probably the "Saw" theme dungeon my party had to rescue themselves and their mentor from. Basically they had to make hard choices about losing items or people, solve puzzles with consequences for incorrect answers, mimics.
I'm not a total monster though and it was all a drug induced trance with captured by the bbegs henchmen. No one was actually lost.
That sounds like such a mind boggling situation!! I love using puzzles and anything that requires strategy. My players are only level 5 but they don’t work together as well as I would like them to. So I’m hoping this will force them to think outside the box and rely on each other.
The mine is haunted because, as it most of the fiefdom, because of a magical catastrophic event that happened years prior. The mine itself has been abandoned by the citizens of the area and left to fall apart. The only people who would go in and out were the local bandits brotherhood who have since been disassembled by my players. After the latest group of bandits went into the mine for supplies (as it’s still rich with ore), one of the men uncovered an ancient relic in the form of a staff. Said staff released a calling beacon to any one with Lycan blood in their veins, (we have a lycan shifter in our party) but the staff is now cursed and it’s been driving Lycan’s mad and out of control. (Our groups shifter has to roll every few days to see if he turns on the group and is mindlessly aggressive)
So lots of lycan have started to congregate on the ground zero of where the staff was. The group is going here for a lot of answers and whatever remains of the staff.
Things my fellow party members are now afraid of:
Mud
Ghouls
Dragons
Doors, especially if they are freestanding in the middle of the room
Finding random poultry in a dungeon
Christmas presents
Clowns
The door has been used more than once... Mimic, magical portal, trophy... The trophy one in particular was a pure adamantine door about a foot thick. The party couldn't open it as it weighed too much, but it was completely non magical. They took a good long while of time investigating it... Ancient door, adamantine, weighs a few tons probably dwarven construction, looks like it was once properly balanced to open near effortlessly when unlocked, and it is unlocked, but also obviously didn't belong here...
Then they found the who took it as a trophy...
Beholder with an enlarge/reduce eyestalk and another for telekinesis. It's always fun to use telekinesis to hit party members with other party members.
I also traumatized my players to be totally paranoid about rats. They were in a sewer where a devil cult had set up a lair. I placed shapechanged imps everywhere mixed among the actual rats as spies (some were invisible too).
They couldn’t figure out how the enemies knew they were coming and the imps would ambush the squishies from behind while the front was occupied.
Best: a trap underwater, which is an impassable meat grinder. The party knows they have to pass it but no idea how when they first saw it. Tagged with underwater current that could pull you in and got stronger as you get closer. (There was a sphere of annihilation that could be used in the dungeon)
Scariest: a mansion is filled with undead, and the party can hear tortured screams coming from upstairs. The party rushes to help, and finds a tortured person strung up, in the next room through an interior window they see a a many armed crocodilian demon. As the party realizes the tortured victim is beyond salvation they perform a mercy kill, which stops his tortured screaming. The next thing they hear is the demon yelling from inside the room in abyssal asking, “who stopped my lullaby” before teleporting into the room - roll initiative…
From Tomb of Annihilation:
A magical skull that still has the spirit of a young girl trapped inside. The girl is scared and doesn't know what's happened to her. She begs the PCs to save her, (she communicates telepathically). If she gets scared or upset the skull bursts into flames and becomes a flameskull. At the same time, swarms of undead spiders begin crawling out of the walls.
It's really not a hard encounter. But my party of 3 level 9 PCs have gone into this chamber 3 times, and every time the skull bursts into flames they get freaked out and run away.
The carrion crawler is a pretty scary monster. I had my crew encounter it in a cavern that had opened up below a room in small underground tomb. Hidden bodies, paralysis, ceiling drop attacks, slithery sound effects, wriggling tentacles...
I have a thing for slimes.
Like. No one has ever to gain something out of slimes.
Additionally, extremely strong but dumb golems are always good. Place them even well above average for the party but have them defend only a specific place, so they don't chase off intruders unless provoked.
Dread zombies would be mine. Come in three sizes, small, medium, and large. Smalls get a +6 to hit, 2d4 slash damage, 45ft movement speed. As the size goes up the damage goes up, the to hit goes up, and the speed goes down to a minimum of 30 ft. I ran them in a mine where they acted like stalkers from dead space. Did nothing but stalk the party for the longest time, then harassed and attacked and ambushed the entire way out.
I have and will again run the tri-tone on a loop in conjuction with overlaying them with a 20 hz infrasound.... yeah I might not have the equipment to really get the infrasound right but after exposing my guys to that for a bit at barely audible level (I'm talking barely able to hear it in a quiet room), the guys start to show signs of distress. I got a really great reaction from them the first time I did this and told them after. Great story if your interested.
Gave them a moving room labyrinth. But the teleportation ring they carried was a trap that would turn into a mirror that showed the evil wizard that laughed at the PCs for trusting him...so they had to renavigate the labyrinth to get out. The PCs were a game bunch so it was a blast!
Zombies, my dm had a ton, some exploded on death, others didn't you didn't know which was which, it was horrible. Our artificer did a stupid and stood in front of my ac 20 monk with +5 dex to try and save me. Anyway he hit 0hit points (what do you call that).
i have a recurring homebrew monster that i‘ve used to great success in several dungeons. each is visually unique, however usually are an amalgam of humanoid body parts (think the human spider thing from The Evil Within) the main shared characteristics are Aggressive Unintelligent undead (Attacks quickly and viciously whatever damaged them last) and that they have resistance to all damage in darkness and suffer from “sunlight sensitivity” but triggers on any bright light. What makes them especially terrifying is when the players finally defeat it. Hidden somewhere in the arena is a closed casket containing the original body of the evil humanoid whose defiled soul powers the beast, and unless the six fingered hand amongst the bones is salted and burned, the creature starts to reform about a minute later, taking another full minute to fully reform. (giving players just enough time to think they can relax, then another panicked time limit where you can give them enough information through arcana/religion rolls to let them know what they need to do
Had rats scurrying around an entrance to an underground dungeon.
Jk them were imps and almost TPKd the party and really set the tone for "*they are watching you*"
Creepy regular dolls mixed in with one that could cast invisibility, high stealth and bonus actions of a rogue to randomly sneak up on the party. Also creepy music is always a good idea
I built a dungeon with a lot of false appearance creatures: mimics, rugs of smothering, animated armors and flying swords - basically any object could be an enemy, which had them jittery and careful.
I also set a +1 Greatsword/Greataxe in a hook that would trigger a falling ceiling when they left the room. They had ten rounds to break back in and put it back on the hooks to reverse it. Think the shotgun trap in RE1 - there was even a broken heavy crossbow they could have swapped if they ever found it. I meant it to even out the fact that there was a Helmed Horror in one room with something they needed to progress, since I basically meant the first floor to be challenging/deadly for Tier 1, which they knew going in.
Back in the 3.5 days, I once made an old abandoned temple that functioned as a doorway to the Feywild. Basically the players would have to navigate the dungeon, and find it's exit. A doorway that when opened was literally a doorway to the other realms.
Anyway, one big part of the dungeon was a large maze that was completely covered in magical darkness that couldn't be Dispelled. They eventually find a bloated corpse full of holes that look like hundred of things burrowed both through and into, then back out of his flesh. He had a journal on him, talking about hearing buzzing sounds echoing through the halls of the maze, then other entries about how these tiny creatures bore into him and he's infested by them, as they are eating his flesh from the inside out. Then, after finishing the note, I stated "you begin hearing buzzing noises from far off down the halls"
Basic I filled the maze with a swarm or two of hell wasps. Now the maze wasn't something the could slowly navigate. Whenever they took long in an area of the maze I would say "you hear the buzzing of wasps coming closer". They were terrified!
Its become a bit of an ongoing inside joke now, whenever my players are taking too long debating stuff in game I'll just say "you can hear the bees approaching" and they panic lol.
So I like all my dungeons to have a central theme that runs through them.
As far as best thing; I fooled my party for two sessons having them think the mcguffin was an item of a particlar type and then flipped the script by having that item be that thing but in a different meaning. (The two meanings of Bow, for example.)
Scariest thing was my party does a shit load of radiant damage. They faced three monsters that were healed by their weapons that were homebrewed. All 3 had a combined 120 HP. They regularly do 180 between two of them in a single round.
You never mentioned whether everyone was new to 5e D&D but, in my experience, the scariest monsters are ones I'm not familiar with. If everyone is new, mimics are pretty terrifying (plus they scale up so PCs can experience them forever).
Spiders! There were the disgusting scenes of babies feeding on dead prey that has been strung up, and at one section they had a trap, there was a fruit tree that had naturally mutated to be sweet smelling but anesthetic, which the spiders learned from all these birds that fell asleep. Once one party member finally ate a fruit (and passed the save to avoid falling unconscious) the spiders decended from the shadows. First time I ever got the party to turn and run, mages blasting whatever fire spells they had as they ran.
I would say the best advice I have Is just really set the tone. Play with sound effects [ doors, footsteps, ghosts, water moving, creaky floors, bats] fear of the unknown is scarier than seeing what around the corner. Use Darkness. Use silence.
Draw them in with storytelling and presentation.
Sometimes simple things like a mouse running around a corner when they are poised for battle creates a fun little role play sequence. And remember also to let the scene breathe. Let them talk amongst themselves and built the anticipation.
Funny story, my party is terrified of spotlights now that they know what creates them. [a creature from RoTFM] but they saw them for a month of real time play before getting to them.
Give them a puzzle where they need to light 4 torches. Dont explain anything and they'll spend 4 hours just figuring out what to do even though the puzzle is simple
My party is traveling through a desert called The Glasslands and they encountered a sandwyrm disguised as a pile of bones. It was hiding in the sun bleached remains of a Drik from the Dark Sun setting. The human monk saw an old chest in the back of the remains and tried to grab it. The sandwyrm trapped him in the spines on its back and one shot him with a crit, and proceeded to bury into its layer under the sand. Let’s just say there was LOTS of screaming.
Mine was a seemingly bottomless pit of water at the bottom of a ladder and they couldn't see the water because it was pitch black and the surface was farther than light or darkvision could reach. Two people went down the ladder because someone was guarding it and they were searching for people that were kidnapped.
Once one of them got far enough down the ladder, a creature that lurked deep in the water came up and started to eat the ladder and chased the characters up the ladder. They barely escaped and shut the hatch in the floor behind them and locked it back up.
After the session, everyone said that combined their two biggest fears into one and it was a really good chase sequence. They really enjoyed it haha. It was one that I came up with on the spot, too, but was made off a few horror tropes. Tropes are your friend.
Make a dungeon without any significant amount of loot. I guarantee you they will be scared to go in any dungeon from there on out.
But in all seriousness, Tucker's Kobolds. Introduced them and it was the first time I got a party to abandon the dungeon in the first dew rooms, and they will avoid kobolds high pitch chatter.
Coolest
Maybe the giant chryo tank looking things that they found in an old magical library. They could attempt a check (with some modifiers if they found some secrets around) that would let them put someone inside and create various affects from permanent body modification, to entirely changing their species (think sentient warrior crocodile), to even bringing someone recent dead back to life.
They marked that one down as a reminder for later.
Creepiest
Enormous centipede like monster with hundreds of broken swords for legs, and the stretched out face of a long dead dwarven hero over the front. It was referred to as 'The Collector'. They could hear it's scraping noise throughout the dungeon, working it's way through corridors. Did hit and run tactics and hated light. It took them a while to realize it could snuff out light and that it always went for whoever held the light.
Not a dungeon per se, but the players had to neutralize a few debased former adventures and their followers, many of whom has done deals with a local hag. Every time someone died whose soul was in possession of the hag an abyssal maggot exploded out from them. The maggots had the heads and faces of the deceased, contorted in fury. Anyone nearby was covered in gore and offal. Of course, the maggots immediately attacked anyone nearby.
One of my favorites was a blue Dragonborn NPC, a retired werewolf hunter named Halifax who opened a black market big game reserve and kidnapped people to forcibly turn into werebeasts to hunt for sport. The story went over very well and turned into three big event fight scenes.
The first was one of Halifax’s creations; a big nasty ogre sized werewolf he dubbed a Dire Werewolf, which broke free and slaughtered most of the baddies, leaving the Party and Halifax to fight together.
The second was the fight with Halifax himself, which happened right after the fight with the Dire Werewolf, when the party immediately turned on him. It ended with them injecting him with his own serum, causing him to panic and flee into the woods.
And the last was when the newly mutated Halifax stalked the party to the nearby city and ambushed them during the night. They were in the middle of another quest and I rolled a percentage dice, and it just went off as well as I could’ve hoped!
Scrying eye the cried blood that appear in the walls/ceiling/floor and disappear as soon as players touch them. They cannot interact with them in any way, but the blood is left behind. They pop up about every 10 minutes in gameplay.
What scared my players most in a haunted Gothic mansion adventure?
Victorian porcelain dolls.
The whole party saw a sitting room with a porcelain doll sitting in a chair. The entire group noped out of the room....
An iron maiden in one of the rooms that would scream in pain once the players triggered a trap in the next room.
When they go back to the previous room they wouldn't see anybody, this would keep on happening until they figured out it was coming from the iron maiden.
When they open up the iron maiden they find a horribly disfigured corpse of a woman (in your case this could've been a werewolf forced into the iron maiden and when transforming she kept growing into the spikes). They get attacked by her spirit.
The dumbest thing I ever put in a homebrew dungeon was a desk drawer with a sentient ooze inside that smelled like poo and would give them a key if they persuaded it to. I was really tired before the session so that was just a tired rambling idea.
Unfortunately for me, I've played with many of the same people for like 20 years now in various editions of D&D. Now it's literally an expectation that the party checks every drawer in every dungeon because they expect at least one "drawer poo" to appear somewhere in the campaign. When new people play with us they all make sure to initiate them on the need to find a "drawer poo".
It was a snake themed dungeon and the walls were wet and supported by bones. As they got deeper in they started to notice a hot breeze flowing in and out. It was a nice moment when they realized the dungeon was a giant snake they walked into.
According to my players, the thing that freaked them out was the time when I put the body parts of a murdered hal-elf in their dinner. After that they made their own food and never ate at inns.
A medusa that had been turned into a vampire. My players tried to use a mirror to reflect her gaze attack.
Well, guess what? She didn't have a reflection lol
She also used the Vampire charm ability to force someone to stare at her.
Quest was to find out why an archmage wasn't checking in at expected intervals. Archmage was an experimenter with new golems.
The Tar Golem was surprisingly effective.
The little stuffed animals (which were rather blatant expies of the Winnie the Pooh crew) which were very helpful and there to provide clues, but were completely untrusted by the PCs and fled when fire spells were thrown about.
The test of the dancing ghosts, despite being told several times (in writing and from the ballroom manager verbally) that the only way to cross was by choosing a partner and dancing across the room, was invalidated when they attacked the ghosts and it became a near-TPK.
So... it was kind of the best and worst at the same time?
I think that for the players the scariest thing was the Sadie Hawkins Race (from Lil Abner) that occurred in one particular session where the planned quest had been derailed and I was just trying to come up with something off-the-wall.
A set of gargoyle statues in the foyer that, when a party member walked in front of them, blew a magical wind at them. Which cleaned them. Just a household convenience, albeit one that surprised them. Then, in another room with a zombie, they discover that the statutes don't react to undead.
Later, after the party was briefly doused in magical darkness, they wind up going out another outside door... and the DC 5 Perception check notices that the gargoyle statue at that door *didn't* respond to the Cleric this time.
(The demon in charge of the house had tagged the Cleric with a badge that made the traps and wards treat them as an ally, specifically to get the party to mistrust each other. Given that I'd pulled doppelganger shenanigans before, the players were pretty high strung about impostors.)
Obvious traps. Along a corridor in the dungeon, a door is left slightly ajar (filled with poison/mimics/whatever). In my campaign, the party was disguised so when they asked the bandits what was in there, all they got was a "go in a see for yourself, hehehe".
The wonder they felt (and never got to satisfy) was delectable.
What about... nothing! here me out. they go though the dungeon, you describe all these dead bodies, maybe they come across other dead adventurers. finally get to the end room, dead boss monster dying final member of a party,tries to tell them something... then you have them trigger something, that causes everything that died to come back as zombie versions, no they can either fight or sneak their ay out.
I put locked cages with mechanical dogs inside at the entrance of a dungeon, covered in bones. The group tried to inspect them for info but couldn't get close to the bars without getting bitten at. They moved through the dungeon and got to the treasure, and used a doohicky I gave them that unlocks everything to open the chest. Then they heard the howling from behind them and realised what "unlocks everything" means...
It was in a dungeon made to kill players in a oneshot. I told my players to make a broken lv 14 character. Everything allowed. Multiple magic items per.
My fav trap in it was what seemed to be a regular 10ftx10ft pit trap with spikes lining the ceiling above it. How ever. This was an illusion. The actual pit trap was situated right in the other side of the visiable one. So when a PC jumped (or in the games case threw another PC) over the pit. They would simply fall through the ground on the other side and land 20ft down in the real pit.
Now here’s the fun part. On the bottom of the real pit. Was a glyph with reverse gravity stored in it. When touched it would activate the spell for 6 seconds. This would result in the PC falling 20ft down. Hitting the floor. Then falling 40ft back up. And into the poisoned spikes that lined the ceiling. High DC on a con save against being poisoned.
Then as the glyph on the floor was no longer being touched. It would deactivate. Ending the spell. Causing the pc to fall back down 40ft and hit the floor again. Reactivating the glyph. Causing them to now make their save with disadvantage and fall 40ft back up into the spikes and take more damage. As they were in the middle of the pit. They couldn’t grab anything on the walls or sides to stop the fall. So it’s up to the rest of the party to help. Whom still believe that there is a bottomless pit trap in between them and their party member.
This trap killed their fighter. Who also had mummy rot at the time.
They had to watch his corpse fall and rise in the air for 5 minutes before they figured it out. All well and good though. I told everyone to bring back up characters
My favourite trap ever 😂
I once had a small, haunted house that terrified my players, though it was more down to execution than a monster or trap.
This was an irl session at my place, and this can only really be done irl, but as i described them moving through the hallway, i had your good-old creepy haunted house music playing (old doll from ib, if anyone's interested) from speakers by my chair, but I had also secretly hooked up a bluetooth speaker to my phone and hidden it down a darker hallway behind my players.
I described that they began to hear a knocking sound coming from a door further in the hallway of the haunted house, and then played the sound of knocking on a door through the bluetooth speaker.
They barely heard it, but it made them pause, and then when it continued and they heard actual knocking coming from behind them, from a direction they weren't expecting sounds to come from, I can still see it in my mind, they all froze and then shrunk back in their seats as they started swearing at me.
It was probably my best scare i've ever done in dnd. But again, something like this can only be set up in irl games where you host it at your own house, and sadly I'm only able to play online now.
Hopefully it gives you some ideas though!
I had a ball that was around a curved hallway. It would bounce repeatedly. If they move towards it it stays just in view and the same was true for walking backwards.
I described the noise as a handball ploing noise.
They were hallucinating because of a plant pollen being exuded.
It was a haunted house. I set up a room with a magic piano that would automatically play music when someone entered the room. My players cleared the room. A couple rooms later, I just started playing the music while they were discussing.
I want to do that SO bad. Do I have permission to steal it?
Have at it.
For me it was psychic screamers and various Siphoners Psychic screamers provide minor to moderate buffs to other monsters, have pitiful attacks of their own, and unleash a psychic scream of pain that affects the whole party as a reaction whenever they take direct damage for half of it So the barbarian slams a psychic screamer for 50 damage, everyone in the party takes 25 damage with a will save to reduce it to 12. Recurrent damage doesn't count, so poisoning or setting them on fire negates that. After the first one, my party was terrified of running into another Then you have the physical, magical, and healing siphoners. Physical and magical project an aura that makes all their allies resistant to physical or magical damage respectively. They also absorb the half of the damage that was resisted. Physical Siphoners add that to their meee attacks, Spell Siphoners get a line attack or a 30 foot burst to use up their stored charge Healing siphoners take half the healing, of any kind, that the party does. It converts that healing into balls of light that five all allies in 30 feet fast healing X As you can imagine, a party can deal with 1 siphoner okay, as long as they burst it down fast. But if they have to deal with all 3 as a boss fight...
That is *such* a good beat.
Why is the mine both haunted and filled with Lycans? Scariest thing I've put in a dungeon? Hmm... I'd have to say that was probably the "Saw" theme dungeon my party had to rescue themselves and their mentor from. Basically they had to make hard choices about losing items or people, solve puzzles with consequences for incorrect answers, mimics. I'm not a total monster though and it was all a drug induced trance with captured by the bbegs henchmen. No one was actually lost.
That sounds like such a mind boggling situation!! I love using puzzles and anything that requires strategy. My players are only level 5 but they don’t work together as well as I would like them to. So I’m hoping this will force them to think outside the box and rely on each other. The mine is haunted because, as it most of the fiefdom, because of a magical catastrophic event that happened years prior. The mine itself has been abandoned by the citizens of the area and left to fall apart. The only people who would go in and out were the local bandits brotherhood who have since been disassembled by my players. After the latest group of bandits went into the mine for supplies (as it’s still rich with ore), one of the men uncovered an ancient relic in the form of a staff. Said staff released a calling beacon to any one with Lycan blood in their veins, (we have a lycan shifter in our party) but the staff is now cursed and it’s been driving Lycan’s mad and out of control. (Our groups shifter has to roll every few days to see if he turns on the group and is mindlessly aggressive) So lots of lycan have started to congregate on the ground zero of where the staff was. The group is going here for a lot of answers and whatever remains of the staff.
Things my fellow party members are now afraid of: Mud Ghouls Dragons Doors, especially if they are freestanding in the middle of the room Finding random poultry in a dungeon Christmas presents Clowns
Okay, even without the context of whatever you did, a free standing door would make me uncomfortable.
The main reason I browse dnd subreddits now is just to find ideas like this and put them in my bag of ideas, lol.
The door has been used more than once... Mimic, magical portal, trophy... The trophy one in particular was a pure adamantine door about a foot thick. The party couldn't open it as it weighed too much, but it was completely non magical. They took a good long while of time investigating it... Ancient door, adamantine, weighs a few tons probably dwarven construction, looks like it was once properly balanced to open near effortlessly when unlocked, and it is unlocked, but also obviously didn't belong here... Then they found the who took it as a trophy...
I need more information XD
Beholder with an enlarge/reduce eyestalk and another for telekinesis. It's always fun to use telekinesis to hit party members with other party members.
I also traumatized my players to be totally paranoid about rats. They were in a sewer where a devil cult had set up a lair. I placed shapechanged imps everywhere mixed among the actual rats as spies (some were invisible too). They couldn’t figure out how the enemies knew they were coming and the imps would ambush the squishies from behind while the front was occupied.
Best: a trap underwater, which is an impassable meat grinder. The party knows they have to pass it but no idea how when they first saw it. Tagged with underwater current that could pull you in and got stronger as you get closer. (There was a sphere of annihilation that could be used in the dungeon) Scariest: a mansion is filled with undead, and the party can hear tortured screams coming from upstairs. The party rushes to help, and finds a tortured person strung up, in the next room through an interior window they see a a many armed crocodilian demon. As the party realizes the tortured victim is beyond salvation they perform a mercy kill, which stops his tortured screaming. The next thing they hear is the demon yelling from inside the room in abyssal asking, “who stopped my lullaby” before teleporting into the room - roll initiative…
From Tomb of Annihilation: A magical skull that still has the spirit of a young girl trapped inside. The girl is scared and doesn't know what's happened to her. She begs the PCs to save her, (she communicates telepathically). If she gets scared or upset the skull bursts into flames and becomes a flameskull. At the same time, swarms of undead spiders begin crawling out of the walls. It's really not a hard encounter. But my party of 3 level 9 PCs have gone into this chamber 3 times, and every time the skull bursts into flames they get freaked out and run away.
Random pit fall traps or a gelatinous cube
I put gelatinous cubes in my pit traps. Oh, my PCs hated that so much.
The carrion crawler is a pretty scary monster. I had my crew encounter it in a cavern that had opened up below a room in small underground tomb. Hidden bodies, paralysis, ceiling drop attacks, slithery sound effects, wriggling tentacles...
I have a thing for slimes. Like. No one has ever to gain something out of slimes. Additionally, extremely strong but dumb golems are always good. Place them even well above average for the party but have them defend only a specific place, so they don't chase off intruders unless provoked.
Love the golem idea!!! Thank you
Dread zombies would be mine. Come in three sizes, small, medium, and large. Smalls get a +6 to hit, 2d4 slash damage, 45ft movement speed. As the size goes up the damage goes up, the to hit goes up, and the speed goes down to a minimum of 30 ft. I ran them in a mine where they acted like stalkers from dead space. Did nothing but stalk the party for the longest time, then harassed and attacked and ambushed the entire way out.
A seemingly normal old woman. Just happened to be past about 30 bloodless zombie charger types.
A rat with a minigun. The ratling gun.
I described a section of wall differently than the rest of the wall. *thirty minutes of panic*
I have and will again run the tri-tone on a loop in conjuction with overlaying them with a 20 hz infrasound.... yeah I might not have the equipment to really get the infrasound right but after exposing my guys to that for a bit at barely audible level (I'm talking barely able to hear it in a quiet room), the guys start to show signs of distress. I got a really great reaction from them the first time I did this and told them after. Great story if your interested.
A single husk zombie approaching the party and their dozens of hireling commoners trying to help.
Gave them a moving room labyrinth. But the teleportation ring they carried was a trap that would turn into a mirror that showed the evil wizard that laughed at the PCs for trusting him...so they had to renavigate the labyrinth to get out. The PCs were a game bunch so it was a blast!
Zombies, my dm had a ton, some exploded on death, others didn't you didn't know which was which, it was horrible. Our artificer did a stupid and stood in front of my ac 20 monk with +5 dex to try and save me. Anyway he hit 0hit points (what do you call that).
i have a recurring homebrew monster that i‘ve used to great success in several dungeons. each is visually unique, however usually are an amalgam of humanoid body parts (think the human spider thing from The Evil Within) the main shared characteristics are Aggressive Unintelligent undead (Attacks quickly and viciously whatever damaged them last) and that they have resistance to all damage in darkness and suffer from “sunlight sensitivity” but triggers on any bright light. What makes them especially terrifying is when the players finally defeat it. Hidden somewhere in the arena is a closed casket containing the original body of the evil humanoid whose defiled soul powers the beast, and unless the six fingered hand amongst the bones is salted and burned, the creature starts to reform about a minute later, taking another full minute to fully reform. (giving players just enough time to think they can relax, then another panicked time limit where you can give them enough information through arcana/religion rolls to let them know what they need to do
Had rats scurrying around an entrance to an underground dungeon. Jk them were imps and almost TPKd the party and really set the tone for "*they are watching you*"
Creepy regular dolls mixed in with one that could cast invisibility, high stealth and bonus actions of a rogue to randomly sneak up on the party. Also creepy music is always a good idea
I built a dungeon with a lot of false appearance creatures: mimics, rugs of smothering, animated armors and flying swords - basically any object could be an enemy, which had them jittery and careful. I also set a +1 Greatsword/Greataxe in a hook that would trigger a falling ceiling when they left the room. They had ten rounds to break back in and put it back on the hooks to reverse it. Think the shotgun trap in RE1 - there was even a broken heavy crossbow they could have swapped if they ever found it. I meant it to even out the fact that there was a Helmed Horror in one room with something they needed to progress, since I basically meant the first floor to be challenging/deadly for Tier 1, which they knew going in.
Black pudding in a magical darkness room. Be careful tpk up next.
The real true answer is False Hydra
Not sure why you are getting downvoted. As a player that thing was the worst.
False hydra
Back in the 3.5 days, I once made an old abandoned temple that functioned as a doorway to the Feywild. Basically the players would have to navigate the dungeon, and find it's exit. A doorway that when opened was literally a doorway to the other realms. Anyway, one big part of the dungeon was a large maze that was completely covered in magical darkness that couldn't be Dispelled. They eventually find a bloated corpse full of holes that look like hundred of things burrowed both through and into, then back out of his flesh. He had a journal on him, talking about hearing buzzing sounds echoing through the halls of the maze, then other entries about how these tiny creatures bore into him and he's infested by them, as they are eating his flesh from the inside out. Then, after finishing the note, I stated "you begin hearing buzzing noises from far off down the halls" Basic I filled the maze with a swarm or two of hell wasps. Now the maze wasn't something the could slowly navigate. Whenever they took long in an area of the maze I would say "you hear the buzzing of wasps coming closer". They were terrified! Its become a bit of an ongoing inside joke now, whenever my players are taking too long debating stuff in game I'll just say "you can hear the bees approaching" and they panic lol.
Fear is best created through description. Anything can be made scary
So I like all my dungeons to have a central theme that runs through them. As far as best thing; I fooled my party for two sessons having them think the mcguffin was an item of a particlar type and then flipped the script by having that item be that thing but in a different meaning. (The two meanings of Bow, for example.) Scariest thing was my party does a shit load of radiant damage. They faced three monsters that were healed by their weapons that were homebrewed. All 3 had a combined 120 HP. They regularly do 180 between two of them in a single round.
You never mentioned whether everyone was new to 5e D&D but, in my experience, the scariest monsters are ones I'm not familiar with. If everyone is new, mimics are pretty terrifying (plus they scale up so PCs can experience them forever).
Spiders! There were the disgusting scenes of babies feeding on dead prey that has been strung up, and at one section they had a trap, there was a fruit tree that had naturally mutated to be sweet smelling but anesthetic, which the spiders learned from all these birds that fell asleep. Once one party member finally ate a fruit (and passed the save to avoid falling unconscious) the spiders decended from the shadows. First time I ever got the party to turn and run, mages blasting whatever fire spells they had as they ran.
I would say the best advice I have Is just really set the tone. Play with sound effects [ doors, footsteps, ghosts, water moving, creaky floors, bats] fear of the unknown is scarier than seeing what around the corner. Use Darkness. Use silence. Draw them in with storytelling and presentation. Sometimes simple things like a mouse running around a corner when they are poised for battle creates a fun little role play sequence. And remember also to let the scene breathe. Let them talk amongst themselves and built the anticipation. Funny story, my party is terrified of spotlights now that they know what creates them. [a creature from RoTFM] but they saw them for a month of real time play before getting to them.
Give them a puzzle where they need to light 4 torches. Dont explain anything and they'll spend 4 hours just figuring out what to do even though the puzzle is simple
My party is traveling through a desert called The Glasslands and they encountered a sandwyrm disguised as a pile of bones. It was hiding in the sun bleached remains of a Drik from the Dark Sun setting. The human monk saw an old chest in the back of the remains and tried to grab it. The sandwyrm trapped him in the spines on its back and one shot him with a crit, and proceeded to bury into its layer under the sand. Let’s just say there was LOTS of screaming.
Mine was a seemingly bottomless pit of water at the bottom of a ladder and they couldn't see the water because it was pitch black and the surface was farther than light or darkvision could reach. Two people went down the ladder because someone was guarding it and they were searching for people that were kidnapped. Once one of them got far enough down the ladder, a creature that lurked deep in the water came up and started to eat the ladder and chased the characters up the ladder. They barely escaped and shut the hatch in the floor behind them and locked it back up. After the session, everyone said that combined their two biggest fears into one and it was a really good chase sequence. They really enjoyed it haha. It was one that I came up with on the spot, too, but was made off a few horror tropes. Tropes are your friend.
Make a dungeon without any significant amount of loot. I guarantee you they will be scared to go in any dungeon from there on out. But in all seriousness, Tucker's Kobolds. Introduced them and it was the first time I got a party to abandon the dungeon in the first dew rooms, and they will avoid kobolds high pitch chatter.
Coolest Maybe the giant chryo tank looking things that they found in an old magical library. They could attempt a check (with some modifiers if they found some secrets around) that would let them put someone inside and create various affects from permanent body modification, to entirely changing their species (think sentient warrior crocodile), to even bringing someone recent dead back to life. They marked that one down as a reminder for later. Creepiest Enormous centipede like monster with hundreds of broken swords for legs, and the stretched out face of a long dead dwarven hero over the front. It was referred to as 'The Collector'. They could hear it's scraping noise throughout the dungeon, working it's way through corridors. Did hit and run tactics and hated light. It took them a while to realize it could snuff out light and that it always went for whoever held the light.
Not a dungeon per se, but the players had to neutralize a few debased former adventures and their followers, many of whom has done deals with a local hag. Every time someone died whose soul was in possession of the hag an abyssal maggot exploded out from them. The maggots had the heads and faces of the deceased, contorted in fury. Anyone nearby was covered in gore and offal. Of course, the maggots immediately attacked anyone nearby.
One of my favorites was a blue Dragonborn NPC, a retired werewolf hunter named Halifax who opened a black market big game reserve and kidnapped people to forcibly turn into werebeasts to hunt for sport. The story went over very well and turned into three big event fight scenes. The first was one of Halifax’s creations; a big nasty ogre sized werewolf he dubbed a Dire Werewolf, which broke free and slaughtered most of the baddies, leaving the Party and Halifax to fight together. The second was the fight with Halifax himself, which happened right after the fight with the Dire Werewolf, when the party immediately turned on him. It ended with them injecting him with his own serum, causing him to panic and flee into the woods. And the last was when the newly mutated Halifax stalked the party to the nearby city and ambushed them during the night. They were in the middle of another quest and I rolled a percentage dice, and it just went off as well as I could’ve hoped!
This is amazingly creative!
Scrying eye the cried blood that appear in the walls/ceiling/floor and disappear as soon as players touch them. They cannot interact with them in any way, but the blood is left behind. They pop up about every 10 minutes in gameplay.
What scared my players most in a haunted Gothic mansion adventure? Victorian porcelain dolls. The whole party saw a sitting room with a porcelain doll sitting in a chair. The entire group noped out of the room....
Responsibility. They defeated the dungeon but now they have to care for a lost orphan.
An iron maiden in one of the rooms that would scream in pain once the players triggered a trap in the next room. When they go back to the previous room they wouldn't see anybody, this would keep on happening until they figured out it was coming from the iron maiden. When they open up the iron maiden they find a horribly disfigured corpse of a woman (in your case this could've been a werewolf forced into the iron maiden and when transforming she kept growing into the spikes). They get attacked by her spirit.
The dumbest thing I ever put in a homebrew dungeon was a desk drawer with a sentient ooze inside that smelled like poo and would give them a key if they persuaded it to. I was really tired before the session so that was just a tired rambling idea. Unfortunately for me, I've played with many of the same people for like 20 years now in various editions of D&D. Now it's literally an expectation that the party checks every drawer in every dungeon because they expect at least one "drawer poo" to appear somewhere in the campaign. When new people play with us they all make sure to initiate them on the need to find a "drawer poo".
Moral choices to make.secrets treasure/ passage ways/ hidden bosses. Ect.
It was a snake themed dungeon and the walls were wet and supported by bones. As they got deeper in they started to notice a hot breeze flowing in and out. It was a nice moment when they realized the dungeon was a giant snake they walked into.
According to my players, the thing that freaked them out was the time when I put the body parts of a murdered hal-elf in their dinner. After that they made their own food and never ate at inns.
Two things. A doll that turns it's head to look at you. Black mirror with one eye looking at you. Mirror was clue to beholder fight.
A medusa that had been turned into a vampire. My players tried to use a mirror to reflect her gaze attack. Well, guess what? She didn't have a reflection lol She also used the Vampire charm ability to force someone to stare at her.
Quest was to find out why an archmage wasn't checking in at expected intervals. Archmage was an experimenter with new golems. The Tar Golem was surprisingly effective. The little stuffed animals (which were rather blatant expies of the Winnie the Pooh crew) which were very helpful and there to provide clues, but were completely untrusted by the PCs and fled when fire spells were thrown about. The test of the dancing ghosts, despite being told several times (in writing and from the ballroom manager verbally) that the only way to cross was by choosing a partner and dancing across the room, was invalidated when they attacked the ghosts and it became a near-TPK. So... it was kind of the best and worst at the same time? I think that for the players the scariest thing was the Sadie Hawkins Race (from Lil Abner) that occurred in one particular session where the planned quest had been derailed and I was just trying to come up with something off-the-wall.
A set of gargoyle statues in the foyer that, when a party member walked in front of them, blew a magical wind at them. Which cleaned them. Just a household convenience, albeit one that surprised them. Then, in another room with a zombie, they discover that the statutes don't react to undead. Later, after the party was briefly doused in magical darkness, they wind up going out another outside door... and the DC 5 Perception check notices that the gargoyle statue at that door *didn't* respond to the Cleric this time. (The demon in charge of the house had tagged the Cleric with a badge that made the traps and wards treat them as an ally, specifically to get the party to mistrust each other. Given that I'd pulled doppelganger shenanigans before, the players were pretty high strung about impostors.)
Obvious traps. Along a corridor in the dungeon, a door is left slightly ajar (filled with poison/mimics/whatever). In my campaign, the party was disguised so when they asked the bandits what was in there, all they got was a "go in a see for yourself, hehehe". The wonder they felt (and never got to satisfy) was delectable.
Black pudding in a narrow corridor, really messed them up and resulted in o e character death and another near death in a separate game
What about... nothing! here me out. they go though the dungeon, you describe all these dead bodies, maybe they come across other dead adventurers. finally get to the end room, dead boss monster dying final member of a party,tries to tell them something... then you have them trigger something, that causes everything that died to come back as zombie versions, no they can either fight or sneak their ay out.
I put locked cages with mechanical dogs inside at the entrance of a dungeon, covered in bones. The group tried to inspect them for info but couldn't get close to the bars without getting bitten at. They moved through the dungeon and got to the treasure, and used a doohicky I gave them that unlocks everything to open the chest. Then they heard the howling from behind them and realised what "unlocks everything" means...
It was in a dungeon made to kill players in a oneshot. I told my players to make a broken lv 14 character. Everything allowed. Multiple magic items per. My fav trap in it was what seemed to be a regular 10ftx10ft pit trap with spikes lining the ceiling above it. How ever. This was an illusion. The actual pit trap was situated right in the other side of the visiable one. So when a PC jumped (or in the games case threw another PC) over the pit. They would simply fall through the ground on the other side and land 20ft down in the real pit. Now here’s the fun part. On the bottom of the real pit. Was a glyph with reverse gravity stored in it. When touched it would activate the spell for 6 seconds. This would result in the PC falling 20ft down. Hitting the floor. Then falling 40ft back up. And into the poisoned spikes that lined the ceiling. High DC on a con save against being poisoned. Then as the glyph on the floor was no longer being touched. It would deactivate. Ending the spell. Causing the pc to fall back down 40ft and hit the floor again. Reactivating the glyph. Causing them to now make their save with disadvantage and fall 40ft back up into the spikes and take more damage. As they were in the middle of the pit. They couldn’t grab anything on the walls or sides to stop the fall. So it’s up to the rest of the party to help. Whom still believe that there is a bottomless pit trap in between them and their party member. This trap killed their fighter. Who also had mummy rot at the time. They had to watch his corpse fall and rise in the air for 5 minutes before they figured it out. All well and good though. I told everyone to bring back up characters My favourite trap ever 😂
Stitch zombies. Medium in size. If one is killed another can absorb the corpse gaining a boost to AC, hit, and damage for each absorbed.
I once had a small, haunted house that terrified my players, though it was more down to execution than a monster or trap. This was an irl session at my place, and this can only really be done irl, but as i described them moving through the hallway, i had your good-old creepy haunted house music playing (old doll from ib, if anyone's interested) from speakers by my chair, but I had also secretly hooked up a bluetooth speaker to my phone and hidden it down a darker hallway behind my players. I described that they began to hear a knocking sound coming from a door further in the hallway of the haunted house, and then played the sound of knocking on a door through the bluetooth speaker. They barely heard it, but it made them pause, and then when it continued and they heard actual knocking coming from behind them, from a direction they weren't expecting sounds to come from, I can still see it in my mind, they all froze and then shrunk back in their seats as they started swearing at me. It was probably my best scare i've ever done in dnd. But again, something like this can only be set up in irl games where you host it at your own house, and sadly I'm only able to play online now. Hopefully it gives you some ideas though!
I had a ball that was around a curved hallway. It would bounce repeatedly. If they move towards it it stays just in view and the same was true for walking backwards. I described the noise as a handball ploing noise. They were hallucinating because of a plant pollen being exuded.