Medusa was a beautiful gorgon but she was the only mortal of the 3 sisters.
Medusa was so beautiful that men went to Athens temple to get a glance of her beauty.
Soon Athena got jealous of medusa's beauty and went to Athens temple to curse medusa and to make her ugly but she also gave medusa the gift of eyes to turn people into stone for protection against hunters that looked into her cold eyes.
Lots of men attempted to claim the prize from Medusa. Her head.
Zeus wanted someone brave to go and slay Medusa for her head
Perseus was the chosen one for this dangerous quest.