Wendigo, Eternal Hunger

Fear, Lifelink
Each opponent sacrifices a creature when this
card transforms.
When a creature is sacrificed, you may gain 3
life or put a Hunger counter on this card. For
each Hunger counter, Wendigo gets +1/+1. If
this card has 5 or more Hunger counters on it, it becomes Indestructible.
{4},{t}: Sacrifice a creature. Target opponent
sacrifices a creature.