Shapechanger. The wereshark can use its action to polymorph into a Large shark-humanoid hybrid or into a Large shark, or back into its true form, which is humanoid. Its statistics, other than its size and AC, are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

Blood Frenzy (Shark or Hybrid Form Only). The wereshark has advantage on melee attack rolls against any creature that doesn't have all its hit points.

Water Breathing (Shark or Hybrid Form Only). In hybrid form, the wereshark can breathe underwater. When in shark form, it can only breathe underwater.

Keen Smell (Shark or Hybrid Form Only). The wereshark has advantage on Wisdom (Perception) checks that rely on smell when it is in water.

Multiattack. In humanoid form, the wereshark makes two scimitar attacks. In shark form, the wereshark makes one bite attack. In hybrid form, the wereshark makes two attacks, only one of which can be a bite.

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

Scimitar (Humanoid or Hybrid Form Only). Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 7 (1d6 + 4) slashing damage.