Rusty Grate Pit
HAZARD 6 +10 (expert), or 0 if the grate is open
The rusty grate covers a pit that's 10 feet in diameter and 40 feet deep.
DC 18 Thievery to harmlessly trigger the trap by nudging the gate or the dangling winch, or DC 24 Thievery to stabilize the grate so it doesn't collapse.
AC 21; Fort +17, Ref +11
Hardness 14, HP 56 (BT 28); Immunities critical hits, precision
Pitfall
A creature walks onto the grate
The triggering creature falls in and takes falling damage (20 bludgeoning damage). That creature can use the Grab an Edge reaction to avoid falling.
Whether or not the creature Grabs an Edge, the rusty winch above crashes down atop the triggering creature, dealing 3d10 bludgeoning damage and dislodging its grip (DC 24 basic Reflex save). The creature can still try to Grab an Edge again.
Pathfinder #164: Hands of the DevilOGL