In ancient Greek mythology, Perseus used Medusa’s head to turn Atlas into stone.
The episode appears in Ovid’s Metamorphoses. After killing Medusa, Perseus was traveling with her severed head when he encountered Atlas, the Titan associated with bearing the heavens. Atlas refused Perseus hospitality because of a prophecy that a son of Zeus would one day take his golden apples.
Perseus then displayed Medusa’s head, whose gaze retained its petrifying power even after death. Atlas was transformed into the mountain range known as Atlas, explaining the mythological origin of the mountains in North Africa.
This story is separate from Perseus’s later use of the head against King Polydectes and other enemies. It also differs from Heracles’ encounter with Atlas during the quest for the golden apples; the two heroes appear in related but distinct myths.