uncommon cn large aberration swarm 

Perception +14; darkvision, scent (imprecise) 30 feet

Skills Acrobatics +15, Survival +12

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

AC  23; Fort +14, Ref +17, Will +12

HP 70; Immunities acid, precision, swarm mind; Weaknesses area damage 5; Resistances bludgeoning 9, piercing 5, slashing 5

Bounce [R] Trigger A creature that the gibtas spawn swarm can see targets the swarm with an attack; Effect The swarm bounces to the side and gains a +2 circumstance bonus to AC against the triggering attack. After the attack, the swarm can Stride up to its Speed in a straight line as part of the reaction.

Speed 20 feet

Bounding Swarm The gibtas spawn swarm moves in loping bounces. The swarm ignores difficult terrain.

Swarming Bites [>] Each enemy in the swarm's space takes 2d8 piercing damage and 1d6 acid damage (DC 22 basic Reflex save). A creature that fails its save against Swarming Bites also takes 1d4 persistent acid damage.

Abomination Vaults #2: Hands of the Devil, page 80.