pf2e.fyi
From Pathfinder Society Scenario #6-17: The Devil in the Details, which isn't enabled.

Sargassum Bud Pile

HAZARD 9
Stealth +20 (expert)
Description Sargassum heaps that have only started to grow have no intelligence, but are incredibly tenacious and can reflexively grab onto nearby prey. They obtain nutrients by drowning prey in the water they grow in.

Disable DC 32 Athletics (expert) to rip the reflexive tendrils off the bud or DC 32 Thievery (expert) to trigger the tendrils beforehand and keep them occupied.

AC 20; Fort +21
HP 180 (BT 90); Immunities critical hits, precision, unconscious; Weaknesses slashing 10; Resistances cold 10

Tendril Entanglement
Trigger a creature moves into a square adjacent to the bud pile or into the square the bud pile occupies

Effect The sargassum bud pile whips out numerous tendrils, attempting to grab the creature. The target must attempt a DC 28 Reflex save.

Critical Success The target dodges the tendril and is unaffected.

Success A couple of tendrils latch on to the target. The target becomes Grabbed. The target can Escape by attempting an Athletics or Acrobatics skill check of DC 28.

Failure Several tendrils grab the target. The target becomes grabbed and must make a DC 30 Fortitude or fall Prone. If the target cannot breathe in water, they begin to suffocate. The DC to Escape increases to 30.

Critical Failure As failure, except the DC to Escape increases to 35.

Reset 1 hour if the bud pile has something in its grasps. 1 round if the bud pile has nothing in its grasps.
Pathfinder Society Scenario #6-17: The Devil in the DetailsORC