Scylla was a supernatural female creature, with 12 feet and six heads on long snaky necks, each head having a triple row of sharklike teeth, while her loins were girdled by the heads of baying dogs. From her lair in a cave she devoured whatever ventured within reach, including six of Odysseus’s companions.
Scylla was originally a beautiful sea nymph and the daughter of Phorcys. She was pursued by the sea-god Glaucus, but fled from him because of his piscine features. As a result, Glaucus went to the sorceress Circe to procure a love potion for Scylla. However Circe, who was in love with him, instead poured a potion into the pool where Scylla was bathing, turning her into a hideous monster.
Scylla lived in the Strait of Messina opposite Charybdis, eating all sailors who passed her rock. This left them with the option to either sail close to Scylla and be eaten or sail close to Charybdis and be sunk.
When the Greek hero Odysseus sailed through the Strait of Messina, he, warned by Circe, sailed close to Scylla, as she could only eat six men, whereas Charybdis could and would destroy his ship and kill all the crew. Scylla did indeed eat six men, but Odysseus and the majority of his crew got through unharmed.