Poison Gas

Exits: 1
Pressure plates are scattered about with other types of tiles, only one type is a poison gas sprayer, but the others may have similar effects.
DC 12 Perception to notice the tiles are strange and have a small tube sticking into the chamber.
DC 15 to notice whether it's an poisonous sprayer.
They may deal 0 or 4d10 acid damage, depending on what type they are.
It requires a DC 15 Dex check or Perception to safely cross the hall.