He uses the mirrored back of the Aegis to strike at Medusa without looking her in the eyes. He beheaded her, and then put the head in a sack.
Polydectes.
To slay Medusa.
Though she was not exactly a 'beast', Perseus was known for slaying a monster, the gorgon Medusa.
Perseus was sent to slay Medusa and bring back her head.
The god Hermes aided Perseus by providing him with a sword to slay Medusa and a reflective shield to avoid looking directly at her. Additionally, Athena helped Perseus by giving him a polished shield to help him safely approach Medusa.
Perseus faces external conflict with the gods, particularly with the character of King Polydectes. Polydectes sends Perseus on a perilous quest to slay Medusa in order to get rid of him within the story of Greek mythology.
because perseus killed medusa
He must outsmart the Graiae who guarded the cave where Medusa slept. Then he must not meet Medusa's gaze which turned everyone to stone. The shiny shield that Athena had lent him he used as a mirror when beheading Medusa.
Medusa died when Perseus slayed her. Perseus was the grandson of Zeus.
Perseus was the slayer of Medusa and owner of winged sandals.
Perseus receives gifts from the gods in the book "Perseus". Hermes gives him a sword, Athena provides a polished shield, Hades lends him his helmet of invisibility, and Zeus gifts him with winged sandals. These gifts help Perseus on his quest to slay Medusa and save Andromeda.
Its because he wants to take off her head so she can turn the guy who is trapping his mom into stone to save his mom.