From Pathfinder Adventure: A Few Flowers More, which isn't enabled.

Hidden Spiked Pit

HAZARD 2

Stealth +11 (trained) or DC 0 if the trapdoor is disabled or broken

Description A wooden trapdoor covers a pit that's 10 feet square and 20 feet deep. Knives are arrayed at the bottom of the trap, impaling anyone who falls on them.

Disable DC 18 Thievery (trained) to remove the trapdoor

AC 15; Fort +5, Ref +5

Hardness 7, HP 30 (BT 15); Immunities critical hits, precision

Pitfall

Trigger A creature walks onto the trapdoor

Effect The triggering creature falls in and takes falling damage (10 bludgeoning damage) as well as 2d6 piercing damage from falling on to the knives. That creature can use the Grab an Edge reaction to avoid falling.

Reset Creatures can still fall into the trap, but the trapdoor must be reset manually for the trap to become Hidden again.

Pathfinder Adventure: A Few Flowers MoreOGL