Bat

Echolocation. The bat can't use blindsight while deafened.

Keen Hearing. The bat has advantage on Perception checks that rely on hearing.

Bite. Melee Weapon Attack: +2 to hit, reach 5 ft., one target. Hit: 1 piercing damage. If this damage would reduce a Small or larger target to 0 hit points the target takes no damage from this attack.