From Pathfinder #157: Devil at the Dreaming Palace, which isn't enabled.

Hidden Chute

HAZARD 3

Stealth +13 (trained)

Description A trapdoor in the floor conceals a stone chute.

Disable DC 20 Thievery (trained) to remove the trapdoor or lock it in position using a catch hidden inside the room's doorframe

AC 12; Fort +10, Ref +6

Hardness 5, HP 30 (BT 15); Immunities precision, critical hits

Pitfall

Trigger A creature walks onto the trapdoor

Effect The triggering creature falls 30 feet down the shaft to area E33, taking 15 bludgeoning damage and landing Prone in the ochre jelly's pit. The creature can Grab an Edge to avoid falling.

The DC to Climb the walls or Grab an Edge is 22.

Pathfinder #157: Devil at the Dreaming PalaceOGL