#dnd trap

At first glance, the room holding this trap appears to be empty, but once the intruders trigger the rune in the center of the room, the trap is sprung. The exits immediately seal with powerful magic and from the walls come Shadows. However, the Shadows are far from alone. All along the walls mouths erupt from the stone, and haunting wails fill the room.

A number of Shadows equal to the number of characters in the room pull themselves from the wall. They will attack without mercy and will do their best to kill any who were in the room when they awoke. Even if the intruders manage to escape the room, the Shadows will continue to hunt them until they are killed.

On initiative count 20, the mouths on the wall cause one of the following effects. The same effect cannot be used two turns in a row. Undead creatures are immune to the effects:

Chuckling Cacophony: All creatures in the room must make a DC 13 Wisdom saving throw or fall prone in a fit of uncontrollable laughter. While laughing the creature is considered incapacitated. This effect ends when the creature takes damage.

Haunting Melody: All creatures in the room must make a DC 13 Charisma saving throw or be charmed. While charmed in this manner, they will use all movement to reach the walls of the room. They will then spend their action singing along to the melody. This effect ends when the creature takes damage.

Spawn Shadows: Shadows crawl from the mouths lining the walls. 1d4 Shadows appear in the room.

The trap can be disarmed by destroying the central glyph in the room. It can be destroyed instantly with dispel magic or by dealing a total amount of damage equal to 50, it has an AC of 15. When the glyph is destroyed the mouths on the wall all scream and die. The Shadows are not banished when the rune is destroyed.

What other effects could the room have? Who might use a trap like this? Where would the party be most likely to stumble across this trap?

This trap is different from most other traps. Instead of repelling invaders or outright killing those who find themselves in places they shouldn’t be, this trap is built to draw intruders inside.

This trap is normally centered around a specialized and highly deadly toxin. When this trap is triggered, darts tipped with the poison spring from the wall. Everyone in the room must make a DC 15 Dexterity saving throw. On a failure, the creature is hit by a dart and infected with a deadly disease known as Boiling Blood.

A creature infected with Boiling Blood has disadvantage on all ability checks, saving throws, and attack rolls. If a creature doesn’t receive the cure within an hour of being infected, their blood will turn to fire and reduce them to ash. Attempting to cure the infected with magic, causes the infected creature to take 1d10 fire damage.

The only cure for Boiling Blood is extremely rare and hard to produce. Those that employ one of these traps, will often dangle the cure in front of the intruders. Luring them in deeper and deeper.

The trap can be spotted with a successful DC 15 Perception check and can be disarmed with a successful DC 18 Thieves’ Tool Check. If the disarm check fails by 5 or more, the trap is triggered and whoever was attempting to disarm the trap has disadvantage on their save.

Who might use a trap like this? Where might the party be able to buy this poison? Who created it?

This is where the fun began.

Going up the stairs required a athletic check due to how unfriendly they were to go upwards on. If they rolled decently, you got up a decent chunk of the stairs on your turn. If they rolled bad, they might either go a little bit upwards or trip and fall a few stairs down. If they rolled really badly, they might go to the bottom of the stairs, knocking down any enemies (and players) who were underneath them. The one holding the artifact had disadvantage on this roll. Do keep in mind, a ton of enemies were also climbing and pursuing the players as they climbed.

These stairs led to some of the funniest moments I’ve had with my dnd group, including that if people fell unconscious then they had to carry others up the stairs. At one point they almost all reached the top of the stairs until one of them rolled a 1 and knocked everyone down all the stairs. (which at point all the players and enemies were on)

It's a wizard's lair. Automotons work in it, rebuilding each other and resetting traps whenever there is no one in there. 30ft hallway to start, roll a d6 and that many spaces down the hallway is a pit trap (dc20 to spot, DC 16 to avoid, 10ft deep, 1d6 falling damage, Modron waiting at the bottom to attack whomever falls in)

Next room is a series of dart traps. Holes in the walls are only a dc10 to spot. DC 18 to spot the fine trip lines that trip half of the darts. DC20 to spot the plates on the ground that trigger the other half. 6 traps, 1d4 piercing damage, 1d4 poison damage (maybe more for higher levels). I imagine this room as stonework that has a tree's roots growing through the right hand wall and across the floor, makging some of it difficult terrain. This is also the first room that the central conceit of the dungeon can be noticed- there are ghosts linked to the dungeon as well, that only a necromancer or priest focused on death/life can see.

The last room is a math puzzle. A checkered floor requires the players to input the wizards name- Urza- as if the plates were an alphabet. There will be a reflective roof that shows letters on some of the plates as a hint, but this is where the cheat comes in- the triggers under the plates can be held up by the spirits, preventing the input of a digit. If a wrong digit or one out of order is pressed, two duodrons drop in, and need to be fought. This resets the plates.

This does require the players to know the opponent is a cheater. And that he's a trickster.