Wendigo

Dark Feast. A Wendigo can consume enough of a dead or unconscious Humanoid in 18 seconds (3 rounds) to fully heal itself.

Mimicry. The Wendigo can imitate any animal sound or humanoid voices it hears, as loudly as it wants. Wendigo can emit a call for help or sounds of wild game to lure it's prey away from the group or a settlement. If possible, Wendigo tries to stalk a group to learn the voices of its members before luring them in. Though, in desperation, wendigo can confront a group head-on. In such a case, it tries to stun as many enemies it can with its roar, snatch most defenseless member of a group and retreat to a safer place to murder and devour its victim. A creature that hears the sounds can tell they are imitations with a successful DC 13 Wisdom (Insight) check on specific sounds but DC 17 Wisdom (Insight) on generic sounds.

Hunter. The wendigo has advantage on Dexterity (Stealth), Wisdom (Survival) and Wisdom (Perception) checks.

Spider Climb. The Wendigo can climb difficult surfaces, without needing to make an ability check.

Multiattack. The wendigo can make two attacks with its claws and one with its bite  

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 9 (1d8+5) piercing damage plus 7 2d6 necrotic damage. The wendigo regains hit points equal to the necrotic damage dealt, unless the target is a construct or undead.

Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 9 (1d10+5)slashing damage plus 7 (2d6) necrotic damage.  If the target is a Large or smaller creature that the wendigo already hit with two claw attack this turn, the target is grappled (escape DC 15). Until this grapple ends, the creature is restrained and the wendigo can't use its claws against another target.

Frightening Screech (Recharge 5-6):  The wendigo lets out a terrifying screech. Each creature within 40 feet of the wendigo must succeed on a DC 16 Wisdom saving throw or be frightened of it for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Wendigo Psychosis (Costs 2 Actions, 2/day). The wendigo can curse one target within 120 feet of it. The target must make a Wisdom saving throw of 15 or be cursed. The target immediately loses 1d6 of Wisdom points While under the curse the victim loses 1d4 of Wisdom points every turn unless they make a Wisdom saving throw of 17. When a victim's Wisdom reaches 1, they seek an individual of their race to kill and devour. After completing this act, the afflicted individual slumps to the ground.The transformation into a wendigo takes 2d4 rounds as the victim morphs into this monstrosity. Once the transformation is complete, the victim is effectively dead, replaced by a new wendigo. True resurrection, reincarnate, or wish can restore such a victim to life, yet doing so does not harm the new wendigo.

Instinctive Response. The wendigo can make one claw attack against a creature that hits it. This attack is made with advantage.