Scylla was a monster in Greek mythology that lived on one side of a narrow water channel. On the other side resided another infamous monster called Charybdis. The channel was so narrow that if sailors tried to avoid Scylla, they would sail too close to Charybdis and vice versa.
Most sources do not mention the parents of Scylla, although it is vaguely mentioned that its parents may have been Phorkys and Hecate. The monster appears in the Homeric epic Odyssey, in which Odysseus and his shipmates try to return back to their home island Ithaca after the end of the Trojan War. While in Circe's island, the witch mentioned to Odysseus to sail closer to Scylla than Charybdis, as the latter would surely destroy the whole ship, while the former would only eat a few of his men. Odysseus followed her advice, and once they were barely past the narrow channel, they were distracted by Charybdis thus giving Scylla the opportunity to eat six of the crew members.