Swarm of Giant Sea Horses

Gargantuan swarm of Large Beasts, unaligned

Armor Class 13 (natural armor)
Hit Points 63 (6d20)
Speed 0 ft., swim 40 ft.

16 (+3) 15 (+2) 11 (+0) 2 (-4) 12 (+1) 5 (-3)

Damage Resistances bludgeoning, piercing, poison, slashing
Condition Immunities charmed, frightened, grappled, paralyzed, petrified, prone, restrained, stunned
Senses passive Perception 11
Challenge 3 (700 XP)
Proficiency Bonus +2


  • Charge. If the swarm moves at least 20 feet straight toward a target and then hits it with a ram attack on the same turn, the target takes an extra 21 (6d6) bludgeoning damage. If the target is a creature, it must succeed on a DC 13 Strength saving throw or be knocked prone.
  • Swarm. The swarm can occupy another creature’s space and vice versa, and the swarm can move through any opening large enough for a Large sea horse. The swarm can’t regain hit points or gain temporary hit points.
  • Water Breathing. The swarm can breathe only underwater.


  • Ram. Melee Weapon Attack: +5 to hit, reach 0 ft., one target in the swarm’s space. Hit: 17 (4d6 + 3) bludgeoning damage, or 10 (2d6 + 3) bludgeoning damage if the swarm has half of its hit points or fewer.


There are plenty of sea horses in the sea. GMs should feel free to create additional sea horses and swarms to add to those that the patchwork sea horse can summon or to populate the oceans of the campaign.

The sea horse and giant sea horse appear in the official fifth edition rules, but they are presented here for ease of reference as well as a bonus swarm.

Section 15: Copyright Notice

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