pf2e.fyi
From Pathfinder Society Scenario #2-00: The King in Thorns, which isn't enabled.

Mushroom Ring (3-4)

COMPLEX HAZARD 4
Stealth +12 (trained)
Description This mushroom ring forms a portal to the First World, allowing the Thorned Monarch's reinforcements into the Material Plane. When the PCs approach, a creature emerges. Creatures continue to emerge until the mushroom ring is disabled. Disabling the mushroom ring also causes any creatures that have emerged to disappear.

Disable DC 22 Thievery (trained) or DC 22 Nature to rearrange the mushrooms to disrupt the portal (two actions) or Dispel Magic (2nd rank, counteract DC 20) to counteract the magical properties; three successes are required to disable the portal

AC 21; Fort +14, Ref +8
HP 62 (BT 31); Immunities critical hits, precision

Portal (magical)
Trigger The PCs approach the mushroom ring

Effect A Nuglub emerges from the portal to defend it, and the hazard then rolls initiative.
Routine (1 action) A Nuglub emerges from the mushroom ring and defends it. All nuglubs use the mushroom ring's initiative.
Pathfinder Society Scenario #2-00: The King in ThornsOGL