From Pathfinder Bounty #14: The Blackwood Truce, which isn't enabled.

Deep Mud

HAZARD -1

ENVIRONMENTAL

Stealth +2

Description The mud greedily latches onto anything that lands in it, hampering movement.

Disable DC 15 Survival to navigate a safe path along the remaining bits of stone

AC 10

HP 10 (BT 5)

Squelch

Trigger A creature steps in the mud

Effect Deep mud sucks at the creature's feet. The triggering creature must attempt a DC 16 basic Reflex save as they pull against the mud and struggle to stay upright. On a failure, the mud deals 2d4 bludgeoning damage and the creature falls Prone.

Pathfinder Bounty #14: The Blackwood TruceOGL