Swarm, Rat (CR 2)

Tiny Animal (Swarm)
Alignment: Always neutral
Initiative: +2 (Dex); Senses: low-light vision, scent, Listen +6, and Spot +7


AC: 14 (+2 size, +2 Dex), touch 14, flat-footed 12
Hit Dice: 4d8 (13 hp)
Fort +4, Ref +6, Will +2
Speed: 15 ft., climb 15 ft.
Space: 10 ft./0 ft.
Base Attack +4; Grapple -
Attack: Swarm
Full Attack: Swarm
Damage: Swarm 1d6 plus disease
Special Attacks: Distraction, disease
Abilities: Str 1, Dex 15, Con 10, Int 2, Wis 12, Cha 2
Special Qualities: Half damage from slashing and piercing, swarm
Feats: Alertness; Stealthy; Weapon Finesse
Skills: Balance +10, Climb +10, Hide +14, Listen +6, Spot +7, and Swim +10
Advancement: -
Climate/Terrain: Any
Organization: Solitary, pack (2-4 swarms), or infestation (11-20 swarms)
Treasure/Possessions: None

Source: Monster Manual

A squirming, squeaking horde of feral rats surges closer, teeth glistening in their slavering jaws.

A rat swarm is a mass of teeming, famished, disease-ridden rats. A swarm is composed of individuals very much like the rat described in Rat, but in such great numbers, rats can become implacable hunters capable of killing a human with hundreds of bites.

A rat swarm sometimes can be found in the sewers and foundations of human cities.

Combat

A rat swarm seeks to surround and attack any warm-blooded prey it encounters. A swarm deals 1d6 points of damage to any creature whose space it occupies at the end of its move.

Disease (Ex): Filth fever-swarm attack, Fortitude DC 12, incubation period 1d3 days, damage 1d3 Dex and 1d3 Con. The save DC is Constitution-based.

Distraction (Ex): Any living creature that begins its turn with a swarm in its square must succeed on a DC 12 Fortitude save or be nauseated for 1 round. The save DC is Constitution-based.

Skills: Stealthy: +2 on Hide and Move Silently checks. A rat swarm has a +4 racial bonus on Hide and Move Silently checks, and a +8 racial bonus on Balance, Climb, and Swim checks. A rat swarm can always choose to take 10 on all Climb checks, even if rushed or threatened.

A rat swarm uses its Dexterity modifier instead of its Strength modifier for Climb and Swim checks.

A rat swarm has a +8 racial bonus on any Swim check to perform some special action or avoid a hazard. It can always choose to take 10 on a Swim check, even if distracted or endangered. It can use the run action while swimming, provided it swims in a straight line.