The Medusa Instinct is that of righteous indignation in women. Just because it cannot last indefinitely, or risk being outcast from society, does not mean that it has no useful role or task to take on. There are times to fight back with an enemy to their destruction, but the time will come when we ought to let go of our past conflicts and differences. The goal of defeating, or at least escaping the grasp of grudges that we cannot let go, is a vitality in itself, the letting go of the transgressions of others. To be able to forgive is a source of new life for us all.
Medusa was a fair maiden who was abducted and raped by Poseidon in the temple of Athena, and not even the goddess of war heard her cries for help. Now shattered from the assault, she cried out again to Athena, why she had forsaken her. The goddess finally responded by giving her hair made of snakes, to turn any man to stone who dared to gaze in her eyes. As you could imagine, anyone who wandered along the path of her stare could unjustly be rendered a statue for eternity.
Medusa was originally a ravishingly beautiful maiden, sought by many men, but because Poseidon had raped her in Athena's temple, the insulted at the desecration that Athena transformed Medusa's beautiful hair to serpents and made her face so terrible that the sight of it would turn onlookers to stone. The punishment is on both perpetrator and victim, but Medusa is imbued with incredible power by receiving it. However, like any monster myth, it is representative of the temporary and fragile power of pathological narcissism.
Medusa was beheaded by the hero, Perseus, who was sent to obtain her head as a required gift to King Polydectes, who wanted to marry the mother of Perseus. This hero received a mirrored shield from Athena, gold, winged sandals from Hermes, a sword from Hephaestus and Hades's cloak of invisibility. Perseus was able to slay Medusa while looking at the reflection from the mirrored shield he had received from Athena. This is symbolic of the curative powers of having a solid personal boundary against narcissism.
The Medusa Instinct takes the energy of hurt in one's past, and turns it into the power of a lesson learned, and the justice of never making the mistake of losing one's dignity again.