Wendigo

Shapechanger. Wendigos can use its action to polymorph into a wendigo, or into a human, when the Wendigo dies, it reverts back to its true form (the monstrous form).  Its statistics, other than its size, are the same in each form. Any equipment it is wearing or carrying isn't transformed. 

Keen Hearing and Smell. The Wendigo has advantage on Wisdom (Perception) checks that rely on hearing or smell.

Pounce (Wolf or Hybrid Form Only). If the Wendigo moves at least 15 feet straight toward a creature and then hits it with a claw attack on the same turn, that target must succeed on a DC 14 Strength saving throw or be knocked prone. If the target is prone, the Wendigo can make one bite attack against it as a bonus action.

Unending Hunger. The Wendigo has advantage against injured creatures. The Wendigo targets creature that are unconscious. 

Stalker of the Wild. The Wendigo has advantage on stealth and survival checks when stalking a target. 

Multiattack . In humanoid form, the Wendigo makes two attacks, it can attack like a humanoid or make two claw attacks.

Bite (Wolf or Hybrid Form Only). Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 15 (2d10 + 4) piercing damage. If the target is a humanoid, it must succeed on a DC 13 Constitution saving throw or be paralyzed. Until the paralyzed condition ends, the target can make a constitution saving throw at the end of its turn. 

Claw (Wolf or Hybrid Form Only). Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) slashing damage.