Giant Seahorse

Large Beast, Unaligned

AC: 14

Initiative: +1 (11)

HP: 16 (3d10)

Speed: 5 ft., swim 40 ft.

STR
15 (+2)
DEX
12 (+1)
CON
11 (+0)
INT
2 (-4)
WIS
12 (+1)
CHA
5 (-3)

Senses: Passive Perception 11

CR: 1/2 (XP 100; PB +2)

Habitat: Underwater

Water Breathing.

The seahorse can breathe only underwater.

Actions

Ram.

Melee Attack Roll: +4, reach 5 ft. Hit: 9 (2d6 + 2) Bludgeoning damage, or 11 (2d8 + 2) Bludgeoning damage if the seahorse moved 20+ feet straight toward the target immediately before the hit.

Bonus Actions

Bubble Dash.

While underwater, the seahorse moves up to half its Swim Speed without provoking Opportunity Attacks.

Find this creature in the encounter builder

Giant Seahorse

Source: Monster Manual (2025), p. 359 - Licenses and attribution