From Pathfinder #151: The Show Must Go On, which isn't enabled.

Flea Swarm

CREATURE 5

Flea swarms roil across city streets and rural hinterlands in a hissing, scraping scrabble, draining blood from any creatures unfortunate enough to cross their path.

Fleas are little more than a nuisance in most circumstances, but can be lethal when they grow to monstrous proportions or gather in enormous swarms.

Perception +13; low-light vision, scent (imprecise) 30 feet

Skills Acrobatics +14, Athletics +9 (+13 to Jump)

Str -2, Dex +5, Con +4, Int -5, Wis +1, Cha -4

AC 18; Fort +15, Ref +16, Will +6

HP 55; Immunities disease, precision, swarm mind; Weaknesses area damage 4, splash damage 4; Resistances physical 8 (except bludgeoning)

Speed 30 feet

Flea Fever (disease)

Drain from flea fever can't be reduced or recovered from naturally until the disease is cured.

Saving Throw DC 19 Fortitude

Stage 1 Drained 1 (1d4 hours)

Stage 2 drained 1 and Sickened 1 (1 day)

Stage 3 Drained 2 and sickened 1 (1 day)

Stage 4 Drained 3 and sickened 1 (1 day)

Stage 5 dead

Suck Blood

Requirements The flea swarm's last action was Swarming Bites, and it dealt damage to at least one enemy

Effect The flea swarm drinks the creatures' blood. Each victim becomes Drained 1 and the swarm regains 3 healing HP for each victim drained.

Swarming Bites

Each enemy in the swarm's space takes 2d4+7 piercing damage and must attempt a DC 22 basic Reflex save. A creature that fails its save is exposed to flea fever.

Pathfinder #151: The Show Must Go OnOGL