In mythology, folklore and speculative fiction, shapeshifting is the ability to physically transform through an inherently superhuman ability, divine intervention, demonic manipulation, sorcery, spells or having inherited the ability. The idea of shapeshifting is in the oldest forms of totemism and shamanism, as well as the oldest existent literature and epic poems such as the Epic of Gilgamesh and the Iliad. The concept remains a common trope in modern fantasy, children's literature and popular culture.