Your favorite wacky, creative, and overly complex traps?

Mine is the Bridge At Rule Vincent from grimtooth’s traps. For those that don’t know, the trap consists of a narrow walkway over a deep pit of burning oil. A flit golem waits on the bridge, fighting those that attempt to cross. When hit with anything metal (like a sword) it creates a shower of sparks that ignite the flammable gas filling the room.

What are some of the most interesting traps you have seen or created and used yourself?