Wendigo

Multiattack: The Wendigo can make an attack with each of its claws on its turn. 

Claw: The wendigo lashes out with its claws and slashes at an enemy. +4 to hit does 2d6+2 slashing damage. The target must make a DC 10 Wisdom saving throw or suffer the Touch of the Wendigo. This saving throw is only made by the first target hit on the wendigos turn.

Touch of the Wendigo (Recharge 5-6): When the wendigo slashes at a target it attempts to impart some of it's evil essence to them. If the target fails their wisdom saving throw, on that targets next turn they must expend their bonus action to bite the nearest allied player. The bite has +4 to hit and does 1d6 piercing damage. This ability only effects the first target attacked on the Wendigo’s turn.

It came from the mist (Recharge 1-2): If the wendigo successfully attacks a player with its first attack it can use its bonus action to vanish into the mist and reappear behind another target. This target is surprised and the wendigo can make its second claw attack with advantage.