Traps for OSR games (revised)
Some of the OSR bloggers, such as Arnold K. over at Goblin Punch, have been posting some amazing traps. Instead of wracking my brain to come up with more, I cheated and used the lists in The Nameless Grimoire (a supplement for The Nightmares Underneath) for ideas. In this case I used Aspect + Element + Form and then considered how they may be used as trap effects. Here are the best 30:
A room seals, fills mostly with mud or slime. When the goo reached 90% of the room's volume, it then forms a vortex that will suck the liquid and whoever is in it to the Plane of Ooze. If the characters aren't paying close attention they may not understand what happened to them.
The trap conjures a weak creature or a cage made of flesh and bone that will draw a predator. The greater monster will snack on the lesser or cage before trying to eat the player characters, giving them time to potentially escape.
The character who set the trap off is branded as the property of a dao. Soon the genie's servants will come calling for his new slave- and the brand will make it impossible for the character to hide. Removing the brand may be as simple as Remove Curse or as difficult as Limited Wish.
The trap consumes the characters' rations and strengthens the monster in the next room. Or it may rust away one metal object per character, if possible, and empower a metal based golem.
The trap spreads a contagion that will make the characters slightly ill. If they leave the dungeon while sick, the characters will see what the disease really strikes- paths and roads are infected and destroyed. This takes time, but curing any infected route takes a lot more than Cure Disease.
The trap is a large, bulky item that a character should be able to lift and move with great effort. It also steals some of their Intelligence points and if the character wants to use those, they have to be within 5 feet of the object. Getting the points back requires Remove Curse. Destroying the object means the points are lost forever.
Pits that are only visible to those with a specific skill.
The character(s) who set off the trap are enraged and attack an object until their weapon breaks or they fall unconscious.
The whole party suffers amnesia and Disguise Self spells, making them appear to be one of the other characters in the group.
The character who set off the trap is Plane Shifted to an extramdimensional space that appears to be a classroom. It has various NPCs from different parts of the multiverse and the teacher is a hierarch modron. The only way to escape is to make a convincing arguement that the character must be elsewhere. Alignment matters as chaotic characters have a tougher time doing this.
A mind that requires whoever activated the trap to teach it a skill. Failure results in a lot of damage.
A strand from the Fates. Whoever first touches it will gain all the memories of someone who died long ago. What this does to the player character depends on who Strand it is, but permanent Confusion of Feeblemind is a best case senario. (And this was an ironic result considering recent events in Order of the Stick.)
A portal to Sekola's realm (or another marine demon lord) that follows the characters, trying to fool them into taking the dive. It may be a pit in one room, a doorway in another and in a chest in a third. It isn't very intelligent, just cunning enough to nab a character or creature now and again.
The character who tripped the trap sees all metal as if it were gold. Some of the loot in other parts of the dungeon are actually lead or other toxic metals.
Eyes open on the character's gear and inflict dehydration damage to anyone they can see. The water is sent to a mummy and if enough water is added, it becomes some form of aquatic undead.
The character can no longer inflict lethal damage with a manufactured weapon.
All the gems on the character fuse into a minigolem, one that prefers to hunt gnomes over all others.
The character can only hear sounds from Hell. So deafness and possible madness checks, if your game includes them.
A dart that turns any metal it strikes into ore.
A ladder with spined rungs. Anyone using it harms their hands and any cloth or paper they carry is damaged or destroyed (such as Bags of Holding).
A wall or large monolith that falls to sand when the trap is tripped. This may engulf the characters or cause a partial collapse of a cavern.
The trap activates a field that harms those with souls. Remember that in some of the earlier editions, elves had spirits rather than souls and that could apply to many other non-human/demihuman races as well.
The trap is found with ghasts and turns their stench into a minor air elemental. Contact with it is the same as inhaling the ghasts' rotting odor.
The trap conjures a thunderstorm into that room, cave, hallway, etc. Time to break out the Wilderness Survival Guide.
The trap sprays the party with Hellgunk that turns their auras evil. The characters' alignments are unchanged. Hopefully there aren't any paladins around, at least until the auras return to normal days later.
The trap is a statue with a gaze attack, one that causes its victims to lose their sense of direction.
The trap is a statue that answers questioning thoughts out loud in the most negative light possible.
The trap is a chariot that speeds up or slows as its master wills.
The trap is found on or near an underwater river. When it is tripped, the echos and roars become damaging and induce fear as per a dragon.
The trap is a prism that turns light into a cone effect that rusts all ferrous metals. Even a candle will activate the trap.