From Pathfinder #170: Spoken on the Song Wind, which isn't enabled.

Boulder Deadfall Trap

HAZARD 7

Stealth +15 (trained); DC 0 to spot the balanced boulders

Description A weight-sensitive plate buried underneath sand pulls a boulder over a cliff ledge, causing it to fall on targets within the entrance.

Disable DC 27 Crafting (expert) or DC 25 Thievery (expert) to find and disconnect the plate from the tipping mechanism

Deadfall

Trigger A creature enters the area without taking care to avoid the hidden trigger plate

Effect Creatures within 10 feet of the cave entrance take 4d10+18 bludgeoning damage (DC 25 basic Reflex save).

Reset Resetting the boulders in the trap is a labor-intensive project that takes 2 hours.

Pathfinder #170: Spoken on the Song WindOGL