Blood Frenzy. The sahuagin has advantage on melee attack rolls against any creature that doesn't have all its hit points.
Limited Amphibiousness. The sahuagin can breathe air and water, but he needs to be submerged at least once every 4 hours to avoid suffocating.
Shark Telepathy. The sahuagin can magically command any shark within 120 feet of him, using a limited telepathy.
Multiattack. The sahuagin makes three attacks: one with his bite and two with his claws or trident.
Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 9 (2d4 + 4) piercing damage.
Claws. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) slashing damage.
Trident. Melee or Ranged Weapon Attack: +7 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 11 (2d6 + 4) piercing damage, or 13 (2d8 + 4) piercing damage if used with two hands to make a melee attack.