Empusa or Empousa (; Ancient Greek: Ἔμπουσα; plural: Ἔμπουσαι Empusai) is a shape-shifting female being in Greek mythology, said to possess a single leg of copper, commanded by Hecate, whose precise nature is obscure. In Late Antiquity, the empousae have been described as a category of phantoms or spectres, equated with the lamiai and mormolykeia, thought to seduce and feed on young men.