Hunter Shark

Large beast, unaligned
Armor Class 12 (natural armor)
Hit Points 45 (6d10 + 12)
Speed 0 ft., swim 40 ft.
STR
18 (+4)
DEX
13 (+1)
CON
15 (+2)
INT
1 (-5)
WIS
10 (+0)
CHA
4 (-3)
Skills Perception +2
Senses blindsight 30 ft., passive Perception 12
Languages -
Challenge 2 (450 XP)

Blood Frenzy. The shark has advantage on melee attack rolls against any creature that doesn't have all its hit points.

Water Breathing. The shark can breathe only underwater.

ACTIONS

Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) piercing damage.

A hunter shark is 15 to 20 feet long, and usually hunts alone in deep waters.
Monster Manual (SRD) D&D 5 › Monsters