Werecow

Shapechanger. The werecow can use its action to polymorph into a large teeth gaping cow, and it can then polmorph back into its true form. When polymorphed, Its statistics change from a cows to a Werecows. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

Keen Smell. The werecow has advantage on Wisdom (Perception) checks that rely on smell.

Bestial Intimidation. Once until the next night. The Werecow can use its action to cause anybody it faces in a 15ft cone to make a DC 14 Wisdom saving throw or be frightened for 3 rounds. When frightened it uses all of its movement to go away from the werecow. After this ends they must succeed on another DC 14 Wisdom saving throw or be charmed and lured to the werecow for a another 3 rounds. 

Multiattack. The werecow makes two claw attacks.

Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 15 (4d10 + 4) piercing damage. If the target is a humanoid, it must succeed on a DC 14 Constitution saving throw or be cursed with lycanthropy.

Claw. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 13 (4d6 + 4) slashing damage.

Milk Spray (Recharge 5-6). The Werecow uses its udder to spray acidic milk in a 30ft long, 10ft wide line. People within this radius must make a DC 16 Constitution saving throw. They take 21(6d6) acid damage on a failed save and half as much on successful one                               

The Werecow can take 3 legendary actions one at a time and only at the end of another creatures turn. They regain expended actions at the start of its turn. 

Bestial Instincts. When the cow is melee attacked it can use its legendary action to make one claw attack against that creature.

Primitive Reactions. When hit with an attack that deals damage, the werecow can spend its legendary action to move 15ft in any direction.

Liquid Refueling (3 Actions). It uses three legendary actions to regain its Milk Spray attack.