From Pathfinder Bestiary 2, which isn't enabled.

Tick Swarm

CREATURE 9

This swarm of thousands of fist-sized ticks forms a moving carpet of bloated insects-a nauseating and intimidating sight.

Perception +18; darkvision

Skills Athletics +16, Stealth +19

Str +1, Dex +6, Con +4, Int -5, Wis +3, Cha -5

AC 28; Fort +19, Ref +19, Will +14

HP 130; Immunities precision, swarm mind; Weaknesses area damage 10, splash damage 10; Resistances bludgeoning 5, piercing 10, slashing 10

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 ticks cling to the creature and continue biting, dealing 3d6 bleed. Immersion in water reduces the DC of the flat check to end this persistent damage to 5, and any area damage dealt to the creature destroys these clinging ticks.

Speed 25 feet, climb 25 feet

Swarming Bites

Each enemy in the swarm's space takes 3d6 piercing damage (DC 28 basic Reflex save) plus Cling and exposure to tick fever.

Tick Fever (disease)

Saving Throw DC 27 Fortitude

Onset 1 day

Stage 1 Enfeebled 1 (1 day)

Stage 2 Enfeebled 2 (1 day).

Pathfinder Bestiary 2OGL