In Greek mythology, Medusa, the serpent-haired gorgon, was killed by Perseus. Perseus was sent to kill her by the King Polydectes, who was attempting to get Perseus out of the way so he could marry Perseus's mother, Danae.
Perseus was given a number of magical tools, such as a helmet with the power of invisibility and an enchanted shield. With these implements, he was able to sneak up on Medusa and look into the shield to see her without being turned into stone. Then, he utilized the invisibility helmet to escape Medusa's enraged sisters. When Perseus cut off Medusa's head, two creatures were created: Pegasus, a winged horse, and Chrysaor, a golden giant. Perseus traveled back to his home kingdom where he turned Polydectes and his followers to stone with the head of Medusa for harassing his mother.