Large Monstrosity, Chaotic Evil
Traits
Amphibious. The merrow can breathe air and water.
Actions
Multiattack. The merrow makes two attacks, using Bite, Claw, or Harpoon in any combination.
Bite. Melee Attack Roll: +6, reach 5 ft. Hit: 6 (1d4 + 4) Piercing damage, and the target has the Poisoned condition until the end of the merrow's next turn.
Claw. Melee Attack Roll: +6, reach 5 ft. Hit: 9 (2d4 + 4) Slashing damage.
Harpoon. Melee or Ranged Attack Roll: +6, reach 5 ft. or range 20/60 ft. Hit: 11 (2d6 + 4) Piercing damage. If the target is a Large or smaller creature, the merrow pulls the target up to 15 feet straight toward itself.
Found on p.210 of MM2025 (Free Rules)