Wendigo is the most popular name for a kind of cannibalistic ice giant described throughout northeastern Native American folklore. They are also known as witiko, chenook (singular chenoo), giwakwas, and many other spelling variants.
Wendigoag were originally human, but were either possessed by an evil spirit or committed a terrible crime, often cannibalism or causing another person to starve. They have a taste for human flesh, superhuman strength, and are often partially or entirely made of ice. In the place where their hearts should be, they either have their old human body or a chunk of ice, sometimes in the shape of a human. In very rare cases a wendigo can be reverted to human form, but more often than not they must spend the rest of their lives as monsters.
Modern depictions often show wendigo with a deer skull or antlers. However, these attributes have no basis in folklore and were a recent addition by fantasy authors.