Answer:
Medusa was one of the Gorgons, a priestess of Athena who was defiled by the god Poseidon and because of this Act which broke her oath of celibacy, as punishment, her head was covered with snakes and whoever looks at her would turn to stone.
Perseus was tasked with killing and decapitation Medusa and it was an almost impossible task because whoever set eyes on Medusa was turned to stone and he couldn't kill who he cannot set his eyes on.
Therefore he enlisted the help of Athena and Hermes who gave him magical sandals which could fly, an invisibility cloak, a sword and a mirrored shield which was instrumental in killing Medusa and decapitating her.
Perseus found her in her cave as she was sleeping and with the help of the mirrored shield, beheaded her. He was chased by her two sisters but managed to escape their fury with the gifts Athena and Hermes gave to him
