A metal cage drops to seal creatures in a 10-foot square area (no saving throw), and the ceiling of this cage begins to slowly lower to crush those within it , descending at a rate of 1 foot per round from a height of 10 feet.
Creatures inside and outside the trapped area can attempt to open the cage’s single locked door (Disable Device DC 30), but the lock is electrified, automatically dealing 6d6 points of electricity damage with each attempt, and imposing a –1 penalty on the check f or every 5 points of damage dealt in this way. Creatures inside the cage can attempt to hold up the ceiling of the cage as a full-round action with a successful DC 25 Strength check. Success prevents the cage from lowering that round, though it doesn’t reverse the progress or allow egress. Once the height of the cage’s ceiling is 3 feet, Medium creatures take 10d10 points of bludgeoning damage each round the cage’s ceiling is not successfully held up. Once the height of the cage’s ceiling is 1 foot, Small creatures take 10d10 points of bludgeoning damage each round that the ceiling is not successfully held up. Tiny creatures can attempt a DC 30 Escape Artist check to flee through the holes in the cage, Diminutive creatures must succeed at a DC 20 Escape Artist check, and Fine creatures can leave automatically. These traps are often employed in conjunction with an effect that prevents dimensional travel, such as dimensional lock. This addition doesn’t change the trap’s CR, but it does make the trap a combination of mechanical and magical.
Pathfinder Roleplaying Game Horror Adventures © 2016, Paizo Inc.; Authors: John Bennett, Clinton J. Boomer, Logan Bonner, Robert Brookes, Jason Bulmahn, Ross Byers, Jim Groves, Steven Helt, Thurston Hillman, Eric Hindley, Brandon Hodge, Mikko Kallio, Jason Nelson, Tom Phillips, Stephen Radney-MacFarland, Alistair Rigg, Alex Riggs, David N. Ross, F. Wesley Schneider, David Schwartz, Mark Seifter, and Linda Zayas-Palmer.