The constellation named after the Greek hero who slew Medusa is Perseus.
In Greek mythology, Perseus was the son of Zeus and Danaë. King Polydectes sent him to obtain Medusa’s head, a seemingly impossible task because anyone looking directly at the Gorgon would turn to stone. With Athena’s guidance, Perseus used the reflection in a polished shield to approach Medusa safely and behead her while she slept.
The constellation preserves this heroic story in the northern sky. Nearby constellations include Andromeda, Cassiopeia, Cepheus, Cetus, and Pegasus, all connected to related parts of the myth. Perseus is often shown holding Medusa’s severed head, represented by the variable star Algol.
Andromeda is a common mix-up because Perseus rescued her from the sea monster Cetus after killing Medusa. Hercules is another tempting option, but his famous monster-slaying feats belong to a later generation of Greek heroes.