Swarm

A **Swarm**  is a collection of Fine or Diminutive creatures (usually creatures of the vermin or animal types, but not always) that act as a single creature. Swarms include flocks of birds, swarms of bees, writhing nests of poisonous snakes, and any other conglomeration of creatures that tends to move as a solid mass.

A swarm has the characteristics of its original type, except as noted here.

A swarm has a single pool of Hit Dice and hit points, a single initiative modifier, a single speed, and a single Defense. The swarm makes saving throws as a single creature. A single swarm occupies a square (if it is made up of nonflying creatures) or a cube (if comprised of flying creatures) 5 feet on a side, but its reach is 0 feet. To attack, the swarm moves into an opponent's fighting space, which provokes an attack of opportunity. It can occupy the same fighting space as a creature of any size, since it crawls all over its prey. A swarm can move through squares occupied by enemies and vice versa without impediment, although the swarm may provoke an attack of opportunity if it does so. A swarm can move through cracks or holes large enough for its component creatures. Larger swarms are represented by multiple swarms, or multiple 5-foot squares.

Swarms are presented in a variety of sizes, with a typical example of their type.

### Species Traits

Swarms have the following traits:

**Swarm** *:* Swarms are not subject to critical hits or Flanking. A swarm takes half damage from ballistic, slashing, and piercing damage types. It is immune to FX Abilities or effects that target a specific number of creatures (including single-target spells such as Disintegrate) unless the swarm is susceptible to mind-affecting effects. (If it has a mind, it has a single hive mind that can be targeted by a mind-affecting spell, though swarms of vermin are mindless and thus immune to such effects.) A swarm takes a -10 penalty on saving throws against spells or effects that affect an area, such as many evocation spells or grenade-like weapons. If the area effect attack does not allow a saving throw, the swarm takes double damage instead.

A swarm that fails a Fortitude save against massive damage disperses and does not reform until its hit points return to full.

Swarms don't make standard melee attacks. Instead, they deal automatic damage to any creature whose space they occupy at the end of their move, with no attack roll needed. Some swarms also have acid, poison, blood drain, or other special attacks in addition to normal damage. A swarm's attacks are nonmagical unless the swarm's description states otherwise. Damage reduction sufficient to reduce a swarm attack's damage to 0, incorporeality, or other special abilities may make a creature immune (or at least resistant) to damage from the swarm. Swarms cannot attempt trip or grapple checks, nor can they be tripped or grappled themselves.

Swarms do not threaten creatures in their square and do not make attacks of opportunity with their swarm attack. However, they distract foes whose squares they occupy, as described below.

**Distraction (Ex):** Any intelligent creature vulnerable to a swarm's damage that begins its turn with a swarm in its fighting space is distracted. The target must attempt a Fortitude save (DC 10 + swarm's Hit Dice) or become Nauseated for 1 round by the intense pain of countless bites, stings, and pinches. A creature that takes no damage from the swarm's attack is not subject to distraction.

*Nauseated creatures are unable to attack or do anything else requiring attention or concentration; the only action a nauseated creature can take is a single move action per turn.*

Even if the target creature succeeds at a Fortitude save, it is still vulnerable to the swarm's distraction. It is difficult to undertake complex actions while covered by a swarm. Casting or concentrating on a spell requires a Concentration check (DC 20 + spell level). Using skills requiring patience and concentration (such as moving silently or opening a lock) requires a Concentration check (DC 20). If the check fails, the target creature is unable to complete the action.

**Sentience (Ex):** Most swarms have the Intelligence of a single member of the swarm. Sentient swarms have a hive mind. A swarm with a hive mind has a higher Intelligence score but is susceptible to mind-affecting spells as if it was a single intelligent creature. Sentient swarms have skills as a magical beast (2 x.Int score, plus 1 additional skill point per HD beyond 1 HD).