SRD:Rat Swarm

=RAT SWARM=

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: 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.

See Wikipedia Entry: Rat