Crushing Walls and Ceiling
Trap
Level 12 Blaster
XP 700

As you step off the portal, the walls suddenly lurch forward and begin to press in.

Trap: The first and third sections of the chamber are crushing walls traps, while the middle section is a crushing ceiling trap. All sections are activated individually.Perception     DC 16: Scratches in the floors and ceiling make it look as if the walls have moved inward at some point, then back out.Initiative +2(roll separately for each section)TriggerThe chamber is divided into three sections. Each section is triggered when a creature enters the area while standing on the floor.SpecialThe southern section has crushing walls, the central section has a crushing ceiling, and the eastern section has crushing walls. The walls move inward every other turn, while the ceiling moves downward every turn. The walls meet each other and the ceiling meets the floor in the eighth round, assuming no countermeasures are taken.AttackStandard Action      Melee
Target: Creatures in the area of each section of the trap. Once triggered, the walls in the southern and eastern sections move inward 1 square every other turn. Once triggered, the ceiling in the central area moves down 1 square every turn. Creatures adjacent to a wall are pushed 1 square. When the crushing walls come together, or when the ceiling meets the floor, all creatures in the area are slowed and are subject to an attack.
The walls and floor stay in this position for 3 rounds, then move back at 1 square per round and reset.
Attack: +15 vs. FortitudeHit: 3d6 + 6 damage, and the target is immobilized (save ends).Miss: Half damage.Countermeasures     Thievery DC 16: A character adjacent to a wall can delay the trigger 1 round with a successful check.
     Thievery DC 21: A character adjacent to a moving wall can delay its movement for 1 round with a successful check.
     Strength DC 16: A character adjacent to a moving wall or who is tall enough to reach the moving ceiling can prevent the wall or ceiling’s movement with a successful check (+5 to DC if the walls are 1 square apart). All characters in the area can aid the character making this check.
     Perception DC 21: The floors are riddled with niches under secret sliding trapdoors. Opening a trapdoor is a minor action, while slipping into it is a move action. The floor contains one niche per square. Each niche can be occupied by one creature.
A PC in a niche can ride out the crushing walls and ceiling. However, upon leaving a niche and stepping onto the floor again, the section of the trap the PC stands in is triggered once more.

Published in Dungeon Magazine 163, page(s) 43.