Medium Beast, Unaligned
Traits
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 feet of the creature and the ally doesn't have the Incapacitated condition.
Water Breathing. The shark can breathe only underwater.
Actions
Bite. Melee Attack Roll: +4, reach 5 ft. Hit: 7 (2d4 + 2) Piercing damage.
Found on p.368 of MM2025 (Free Rules)