Shapeshifter

In mythology, folklore, and modern fantasy fiction, shapeshifting is the ability of a being able to physically transform into another form or being. By transofrming someone can either form as an inherent faculty of a mythological creature, or by means of magic.

The concept is antiquity, and may indeed be a human cultural universal. This is present in the oldest forms of totemism or shamanism, and is present in the oldest extant literature and epic poems (such as the Gilgamesh Epic or the Iliad). The shape-shifting is usually induced by the act of a deity; it persisted into the literature of the Middle Ages and the modern period (where the agency causing shape-shifting is mostly a sorcerer or witch. This remains a common trope in modern fantasy, children's literature, and works of pop culture.

By far the most common form of shape-shifting is therianthropy which is the transformation of a human being into an animal (or conversely of an animal into human form). Additionally, there can be the transformation into a plant or object, another human form (e.g. fair to ugly, or vice versa), but these transformations are very rare.