Pack Tactics. The shark has advantage on an attack roll against a creature if at least one of the shark's allies is within 5 ft. of the creature and the ally isn't incapacitated.
Water Breathing. The shark can breathe only underwater.
Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 6 (1d8 + 2) piercing damage.