"In Greek mythology, a sea monster who lived underneath a dangerous rock at one side of the Strait of Messia, opposite the whirlpool Charybdis. She threatened passing ships and in the Odyssey ate six of Odysseus' companions. Scylla was a nymph, daughter of Phorcys. The fisherman-turned-sea-god Glaucus fell madly in love with her, but she fled from him onto the land where he could not follow. Dispair filled his heart. He went to the sorceress Circe to ask for a love potion to melt Scylla's heart. As he told his tale of love to Circe, she herself fell in love with him. She wooed him with her sweetest words and looks, but the sea-god would have none of her. Circe was furiously angry, but with Scylla and not with Glaucus. She prepared a vial of very powerful poison and poured it in the pool where Scylla bathed. As soon as the nymph entered the water she was transformed into a frightful monster with twelve feet and six heads, each with three rows of teeth. Below the waist her body was made up of hideous monsters, like dogs, who barked unceasingly. She stood there in utter misery, unable to move, loathing and destroying everything that came into her reach, a peril to all sailors who passed near her. Whenever a ship passed, each of her heads would seize one of the crew. "
P.S. In contemporary Greek, Skylla means bitch (of the female dog variety).