eclectic69:

In Greek mythology Medusa (“guardian, protectress”)[1] was a monster, a Gorgon, generally described as having the face of a hideous human female with living venomous snakes in place of hair. Gazing directly upon her would turn onlookers to stone. Most sources describe her as the daughter of Phorcys and Ceto,[2] though the author Hyginus (Fabulae, 151) interposes a generation and gives Medusa anotherchthonic pair as parents.[3]

Medusa was beheaded by the hero Perseus, who thereafter used her head as a weapon[4] 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.