In Greek mythology, Scylla embodies a sea monster with six heads and twelve legs. She was the daughter of Forkyn (the sea god) and Cratai (the goddess of the sea waves). Other sources state that her mother was Keto (goddess of the seas), and according to some legends she was again the daughter of Echinda and Typhon.
Originally, Scylla was a very beautiful girl. But out of jealousy, the wife of the god Poseidon, Amphitrite, turned her into a monster. Other sources say she was turned into a monster by the sorceress Kirke.
Scylla, along with another sea monster, Charybdis, is described in detail in the myth of Odysseus: "... in the heart of a high rocky mountain, high above the sea, there is a great cave, with thick fog around and within, where Scylla dwells. And even the gods tremble in terror before her. She barks and whines and howls, more terrible than a mammal. It has six pairs of legs, six long necks, a large head at the end of each, an open mouth with three rows of large teeth. When it swims past a boat, it can grab six swimmers at once with those mouths. In a lower rock not far from Scylla lives Charybdis, an underwater monster which three times a day swallows vast quantities of water, drinks up nearly half the sea until the bottom of the sea is visible, and three times a day spews the water out again. If a ship is near, it disappears into the bottomless throat."
Aeneas tells of his voyage from the ruined Troy: "When you come to Sicily, keep always to the left. You must avoid the sea monsters Scylla and Charybdis. Scylla resides on the right bank, hidden in a cave. She resembles a beautiful girl down to her hips and lures the ships to the rock with her charming face. The lower part resembles a monstrous fish. It is covered with blue barking dogs. On the left shore is the predatory Charybdis, which three times a day swallows the immense torrents of water and then throws them up again, the foam splashing up to the clouds."
Only two ships have escaped the Scylla and the Charybdis. The first was an Argonaut ship, but it was helped by many heroes and gods. The second was the ship with Ulysses aboard. It lost six crew members, but made it through.