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Swarm of Miniature Mermaids

Large swarm of Small humanoids (merfolk), neutral

Armor Class 13
Hit Points 60 (11d10)
Speed 10 ft., swim 40 ft.

12 (+1) 16 (+3) 10 (+0) 8 (-1) 14 (+2) 17 (+3)

Skills Perception +4
Damage Resistances bludgeoning, piercing, slashing
Condition Immunities charmed, frightened, grappled, paralyzed, petrified, prone, restrained, stunned
Senses passive Perception 14
Languages Aquan, Common
Challenge 3 (700 XP)

Special Traits

  • Amphibious. The swarm can breathe air and water.
  • Smothering Embrace. While in water, a creature in the swarm’s space is at risk of suffocating. It must succeed on a DC 13 Constitution saving throw to hold its breath or begin choking. A choking creature can survive a number of rounds equal to its Constitution modifier (minimum of 1 round) before dropping to 0 hit points and dying.
  • Swarm. The swarm can occupy another creature’s space and vice versa, and the swarm can move through any opening large enough for a Small mermaid. The swarm can’t regain hit points or gain temporary hit points.


  • Bites. Melee Weapon Attack: +5 to hit, reach 0 ft., one creature in the swarm’s space. Hit: 21 (6d6) piercing damage, or 10 (3d6) piercing damage if the swarm has half of its hit points or fewer.
  • Haunting Melody (recharge 6). The voices of the dozens of miniature mermaids harmonize into a haunting melody. Each creature within 30 feet of the swarm that can hear it must succeed on a DC 13 Charisma saving throw or be charmed by the swarm for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to the swarm’s Haunting Melody for the next 24 hours.