An Empty Room
The walls of this room are studded with giant teeth, yellow and turning to black in places, each one the size of a man's head. More lurk beneath the waterline, hundreds in total, fully calcified and of a single piece with the bone of the walls.
A gleam of gold from beneath the water reveals that one of the teeth has been crudely crowned. Removing it takes D6 rounds of chipping away at the dentistry with pick and blade. Upon release it comes away from the tooth in a solid chunk of gold (450s), allowing the rotting black fluid held back beneath it to gush out into the water.
Those submerged in the water when the abscess is unplugged test Toughness DR 14 or become Infected.