Bites

_Melee Weapon Attack:_ +2 to hit, reach 0 ft., one target in the swarm's space. _Hit:_ 7 (2d6) piercing damage, or 3 (1d6) piercing damage if the swarm has half of its HP or fewer. If the target is a creature, it must make a DC 9 CON save. On a failure, the target contracts the rat plague disease (see Diseased Rats sidebar) or is poisoned until the end of its next turn (the GM's choice).