[Suzerain of Sheol]

I was always fond of the "room of death" from 1st ed. that made it onto the stupidest monsters ever list.

"Hello adventurer. You walk into the room. That's when the floor starts to fight with the ceiling about who gets to eat you. While they fight you sneak along the wall, hoping to escape...only to find out the wall's already starting to digest you the moment you touch it. Adventurer, I hope you've enjoyed your stay in the Room of Death. Remember to fill out your comment card."