Swarm of Mortis Bats
Traits
Echolocation. The swarm can’t use its blindsight while deafened.
Keen Hearing. The swarm has** advantage **on Wisdom (Perception) checks that rely on hearing.
Swarm. The swarm can occupy another creature’s space and vice versa, and the swarm can move through any opening large enough for a Tiny bat. The swarm can’t regain** hit points** or gain temporary** hit points**.
Actions
Bite. Melee Weapon Attack: +0 to hit, reach 5 ft., 1 target. Hit: 2d4 piercing damage plus 1d4 poison damage. The swarm attacks with its Bite.