Swarm of Bats
Medium Beast (Swarm), unaligned
50 XP
Special Abilities
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
Bites
Melee Weapon Attack: +4 to hit, reach 0 ft., one creature in the swarm's space. Hit: 5 (2d4) piercing damage, or 2 (1d4) piercing damage if the swarm has half of its hit points or fewer.
Quick Reference
Running This Encounter
A swarm of bats is difficult to target, requiring the party to make attack rolls against AC 12 with disadvantage if the swarm is below half health due to its evasive nature. Use the swarm's mobility to harass spellcasters and ranged attackers from above. The swarm deals modest damage (22 HP total) but can be a nuisance in confined spaces where escape is limited. Consider using multiple swarms or combining them with other enemies to increase threat level.
Combat Tactics
The swarm uses hit-and-run tactics, focusing attacks on isolated or wounded party members. It attempts to stay airborne and out of melee range, diving to attack then retreating to the ceiling or higher elevations. If reduced below 11 HP, the swarm prioritizes escape over combat.
Environment & Setting
Ideal in caves, dungeons with high ceilings, abandoned towers, or forest canopies where three-dimensional movement provides tactical advantage. Enclosed underground chambers or caverns work best to maximize the swarm's ability to swoop and retreat.