Gorgon

A gorgon (Ancient Greek: γοργών/γοργώ gorgon/gorgo) is a grotesque female creature, their name deriving from the word gorgós 'dreadful'. (Same PIE root as the Sanskrit word गर्जन, garjana 'guttural sound similar to the growling of a beast'. Thus it may have originated as an onomatopoeia.) While gorgons can vary across Greece the term commonly refers to any of three sisters who have hair made of living, venomous snakes, as well as a horrifying visage that turned those who beheld her to stone. Two of the three famous sisters are immortal, Stheno and Euryale, their sister Medusa was not as she was slain by the demigod and hero Perseus. A gorgon's large eyes can be compared to Athena's "flashing" eyes, are considered "the divine (or supernaturally powerful) eyes". Athena's sacred bird, the owl, also has them. Some gorgons have fangs similar to those of a wild boar tusks.

Gorgoneion
A gorgoneion is a stone head, engraving, or drawing of a gorgon face. The images are put upon objects (such as doors, walls, floors, coins, shields, breastplates, and tombstone) and buildings for protection. They are shown with their fangs or with a forced smile displaying large teeth and sometimes a protruding tongue. The flashing eyes are represented by spirals, wheels, concentric circles, (tetra)gammadion, firewheels, and other images. The awkward stance of the gorgon, with arms and legs at angles is closely associated with these symbols as well. Medusa's head was affixed on the aigis and carried by Athena.

Blood taken from the right side of a gorgon could bring the dead back to life, yet blood taken from the left side was an instantly fatal poison. Athena gave a vial of the healing blood to Asklepios, which ultimately brought about his demise.

Herakles obtained a lock of Medusa’s hair (which possessed the same powers as the head) from Athena and to gave it to Sterope, the daughter of Kepheus, as a protection for the town of Tegea.

Sea Sisters
Around 700 BCE, Hesiod reports gorgons as three sea daimons: Stheno (the mighty), Euryale (the far-springer or of the wide sea), and Medusa (the queen). They are the daughters of the sea deities Keto and Phorkys. Their home is on the farthest side of the western ocean, in Libya (North Africa).