Greek mythological figure.

Medusa is the most famous of the three monstrous Gorgon sisters: Stheno, Euryale, and Medusa. The hair of these sisters was a cluster of
writhing snakes, and their faces were so hideous that all who saw them were turned to stone. Only Medusa was mortal. Medusa was once a beautiful woman, but she offended the goddess Athena, who changed her hair into snakes. When Medusa was by Poseidon, Perseus killed her and presented her head to Athena.

Medusa's head retained its petrifying power even after her death. Because of this power, her image frequently appeared on Greek armor.