From Pathfinder Adventure Path: Hell's Destiny, which isn't enabled.

Floor-Be-Gone

HAZARD 12

Stealth +22 (expert)

Description Hinged boards prop the massive paving stones into place on the causeway.

Disable DC 27 Crafting (expert) to reinforce the stones of this causeway or DC 29 Thievery (master) to jam the hinges on the boards

Oops, There It Goes!

Trigger A creature moves through a marked square and fails a secret DC 5 flat check

Effect The board's hinges release, causing the paving stones to drop—along with any creatures in the marked area—to the ground below. Affected creatures can attempt to Grab an Edge (DC 29). Creatures that fall take 4d12+26 bludgeoning damage (DC 29 basic Reflex save) as well as the typical falling damage.

Pathfinder Adventure Path: Hell's DestinyORC