From Pathfinder Kingmaker, which isn't enabled.

Vicious Army Ant Swarm

CREATURE 12

RARE LARGE ANIMAL SWARM

Variant army ant swarm

An army ant swarm is a terrifying carpet of stinging insects that devours all in its path.

Perception +23; darkvision, scent (imprecise) 30 feet

Skills Athletics +16

Str -2, Dex +5, Con +7, Int -5, Wis +5, Cha -4

AC 32; Fort +25, Ref +23, Will +19

HP 155; Immunities precision, swarm mind; Weaknesses area damage 15, splash damage 15; Resistances bludgeoning 8, piercing 15, slashing 15

Swarm Mind

This monster doesn't have a single mind (typically because it's a swarm of smaller creatures), and is immune to mental effects that target only a specific number of creatures. It is still subject to mental effects that affect all creatures in an area.

Cling

Trigger A creature leaves the swarm's space

Effect The swarm takes 1d6 damage as ants cling to the creature and continue biting, dealing 7d6 persistent piercing damage. High winds or immersion in water reduces the DC of the flat check to end this persistent damage to 5. Any area damage dealt to the creature destroys these clinging ants.

Speed 30 feet, climb 30 feet

Swarming Bites (concentrate, manipulate)

Each enemy in the swarm's space takes 7d6 piercing damage (DC 31 basic Fortitude save). A creature that fails its save against Swarming Bites becomes Clumsy 1 for 1 round. If the creature attempts a concentrate or manipulate action while affected, it must succeed at a DC 5 flat check check or the action is lost; roll the check after spending the action, but before any effects are applied.

Effect: Swarming Bites

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