Swarm Immunities
Swarms are immune to the following effects, unless the effect specifies it works against swarms.
- Bleeding, critical hits, flat-footed, off-target, pinned, prone, staggered, and stunned.
- Combat maneuvers—swarms can’t be affected by and can’t perform combat maneuvers, unless the swarm’s description says otherwise.
- Flanking—swarms are unflankable.
- Dying—a swarm reduced to 0 Hit Points breaks up and ceases to exist as a swarm, though individual members of it might survive.
Format: Immunities swarm immunities.
Source
Alien Archive pg. 136