Surprise! It's another list thread from Kobold Cleaver! This actually serves a purpose, though—I'm working on an adventure idea where haunts feature prominently as the villains, encounters, and semi-allies. The main vibe is "crazy trapped dungeon/abandoned magic research facility", but you don't have to stick to that. I'm just trying to get the ideas floating, and it'd be really cool to see what people come up with.
The premise is simple: We're making up ideas for Haunts. You don't need rules, only creativity. Give a basic Haunt personality and the way it tries to kill or hinder its targets. Hell, if you want to make a "friendly" Haunt, go nuts! Come up with a Haunt that hates the PCs' enemies and tries to help the PCs in subtle ways.
1. The Games Room: In life, this eccentric old wizard loved nothing more than clever games and logic puzzles. When her heart stopped right before making the winning move in one such game, her angry spirit lashed out, murdering the rival player before he could "win" himself. She's now desperate to claim her victory, but needs a living player to do it.
The games room contains many board games and riddle books, along with three dead bodies (two unknowing victims like the adventurer, one the original other contestant). At the center is a game of tic-tac-toe. The dead wizard is "O"s, and it was her turn.
Once the entire group enters, the door slams shut and locks, and everyone must begin saving versus confusion every round. The only way to cure the insanity and open the door is to complete the game—but not by making the winning move. If the wizard wins, she is put to rest, the insanity ends, and everything in the room must save or take 1d2 Charisma damage as part of her gleeful gloating. Instead, the stalemate move must be made. Annoyed and disappointed, the wizard will simply leave, ending all effects and opening the door.
If the wizard is somehow made to lose, all must save or take the Charisma damage. The confusion saves must continue, but they and the locked door wear off in 1 minute, and the haunt ends for good.
If the adventurers break out some other way, the confusion wears off after 1 minute.