Sprugcutter had a bad dream that Dennis Rader, the BTK Killer (though in the dream he looked like a shorter version the Rifleman, Chuck Connors), had been a member of KISS, and a short from the Onion News Network had a discussion about how this made a sadistic serial killer seem cool. This trap gives far worse dreams than that. It is triggered by going into a room.
Detect: Per-based Thaumatology, or Perception + Magery for mages, at -7.
Circumvent: Automatic (don't go into the room).
Evade: Resist HT, then Will.
Effects: First everyone in the room must resist HT or fall asleep (Mass Sleep-15), then, for those who failed, must Resist Will or suffer bad dreams (Nightmare-15) and lose 2 FP instead of the normal night's rest.
This is based on the Phantasmal Killer Trap in the Dungeon Masters Guide.