It's Medusa's head, from the greek mythology.
Medusa was a beautiful woman, with wonderful hair, that was unlucky enough to get seduced by Poseidon, in Athena's temple. Outraged by the desecration of her temple, Athena turned her into a feared monster, with snakes instead of hair, that everybody who looked at was instantly turned to stone. Then, the heroic figure of Perseus, sent by Athena and using a bronze shield as a mirror, to avoid looking directly to Medusa, beheaded her while she was asleep.
The myth of Athena and Medusa suggests that Athena, the masculine war goddess, has an anima