Water-Filling Chamber (Elite)
Trap
Level 8 Elite Blaster
XP 700

When a character moves onto a central square in the room, reinforced iron doors crash down over the exits, and a face carved in the wall opens its jaws to spew water into the room. Each iron door can be opened to prevent accidental entrapment, but each door release has three locks.

Trap: The chamber seals off and fills with water when a pressure plate is stepped on.Perception     DC 14: The face carved in the stone walls looks like it has a movable jaw.     DC 19: A portion of the floor gives in when pressed down. It might be a trapdoor or pressure plate.     DC 24: A hidden slot is above each doorway. Something might fall out of it.Initiative +4TriggerThe trap is triggered when a creature enters the trapped square. When triggered, the iron doors fall into place. Roll initiative. On the trap’s initiative count, water begins to pour from the faces in the walls.AttackStandard Action      Area the entire room
Target: Each creature in the areaEffect: On the trap’s initiative count, the water level in the room rises. The water has the following effects each round.
Round 1—No effect on Medium creatures. The room is difficult terrain for Small creatures.
Round 2—The room is difficult terrain for Medium creatures. Small creatures must swim.
Round 3—All creatures must swim.
Round 4—The room is filled with water. All creatures are considered to be swimming underwater.
Countermeasures     Thievery DC 19: A character adjacent to the trapped square can delay the trigger with a successful check.
     Thievery DC 24: A character adjacent to one of the doors can partially prop it open with a successful check. This causes the room to fill with water in twice as many rounds, using the round 1 result on round 2, the round 2 result on round 4, and so on.
     A character adjacent to one of the doors can use a key to open one of its three locks, assuming the character has the right key.
     Thievery DC 19: A character adjacent to one of the doors can open one of its locks with a successful check.
     Strength DC 14: A character adjacent to the carving on the wall can reduce the flow of water into the room for 1 round by partially closing the carving’s mouth with a successful check. For each round that the mouth is held partially closed, water still flows in but at a slower rate. For every 3 rounds that the mouth is held partially closed, the water rises as though a single round had passed (see “Effect,” above).
     Strength DC 30: A character adjacent to one of the doors can attempt to break it down with a successful check.

Published in Dungeon Master's Guide 2, page(s) 67.