Stealth: +12 (trained) (or –10 and no minimum proficiency if the surface is disturbed)
Description: A 15-foot-wide patch of water and sand attempts to submerge creatures that step onto it.
Disable: Survival DC 18 (trained) to disturb the surface
A creature in the quicksand can attempt a DC 20 Athletics check to Swim to either raise itself by one step if it’s submerged to its neck or worse, or to move 5 feet if it’s submerged only up to its waist. On a critical failure, the creature is pulled down one step. A creature that Swims out of the quicksand escapes the hazard and is prone in a space adjacent to the quicksand patch. Other creatures can Aid the creature, typically by using a rope or similar aid, or attempt to pull the creature out with their own DC 20 Athletics check, with the same results as if the creature attempted the check.
Trigger: A Huge or smaller creature walks onto the quicksand Effect: The triggering creature sinks into the quicksand up to its waist. The quicksand rolls initiative if it hasn’t already.
Reset: The hazard still submerges anyone who walks in, but the surface doesn’t become hidden again until it settles over the course of 24 hours.
Source: Core Rulebook pg. 526 2.0