Actions

Bite

Melee Weapon Attack: +4 To Hit, Reach 5ft, One Target. Hit: 4 (1D4+2) Piercing Damage.    

Variant: Diseased Giant Rats

Some Giant Rats carry vile Diseases that they spread with their Bites. A Diseased Giant Rat has a Challenge Rating of 1/8 (25XP) and the following Action instead of its normal Bite Attack.    

Bite

Melee Weapon Attack: +4 To Hit, Reach 5ft, One Target. Hit: 4 (1D4+2) Piercing Damage. If the target is a creature, it must Succeed on a DC 10 Constitution Saving Throw or contract a Disease. Until the Disease is cured, the target can't regain Hit Points except by Magical means, and the target's Hit Point Maximum decreases by 3 (1D6) every 24 Hours. If the target's Hit Point Maximum drops to 0 as a result of this Disease, the target dies.