Head

A Head is a creature type that is not legal in a regular Magic game.

History
Heads were first referred to in the rules text of from Alpha.

Heads reappeared in the Face the Hydra Challenge Deck from the Theros block. Here they were always combined with the creature type Hydra (Hydra Head), and sometimes with the supertype Elite. All cards in the Hydra Deck, including Heads on the battlefield, are colorless and have a converted mana cost of 0. Players can't gain control of any Heads. If a Head would go to any zone other than the Hydra's graveyard, it's put into the Hydra's graveyard instead.

Head finally appeared in the silver-bordered Unstable set, on the card Skull Saucer