In Greek mythology Medusa (Greek: Μέδουσα, 'guardian, protectress') was a Gorgon, a chthonic monster, and a daughter of Phorcys and Ceto. Gazing directly upon her would turn onlookers to stone. She was beheaded by the hero Perseus, who thereafter used her head as a weapon until he gave it to the goddess Athena to place on her shield. In classical antiquity the image of the head of Medusa appeared in the evil-averting device known as the Gorgoneion.