Medusa is a monster from Greek mythology. If she looks at somebody, she turns them to stone because she is very ugly. She is a Gorgon sister. The other two are called Stheno and Euryale and are immortal. All three had brass hands, sharp fangs, and hair that was made out of snakes. The Gorgons were the daughters of Phorcys and Keto.
Medusa used to be a beautiful maiden, but she was caught having sexual intercourse with Poseidon in Athena's temple. Athena then turned Medusa into a horrific sight. No human could look straight at her and live. She was killed by Perseus, who looked at her reflection so he was not turned to stone. He chopped off her head and sent it to Athena. Athena placed the head on her shield for protection. She was also the most horrifying monster yet in Greek mythology.