Scylla was a monster that lived on one side of a narrow channel of water, opposite its counterpart and sister, Charybdis. The two sides of the strait were within an arrow's range of each other; so close that sailors attempting to avoid Charybdis would pass too close to Scylla and vice versa. There are various accounts of her origin and fate. One legend states that Scylla was the daughter of the river god Crataeis and was loved by Glaucus, but Glaucus himself was also loved by the sorceress Circe.
While Scylla was bathing in the sea, the jealous Circe poured a potion into the sea water which caused Scylla to transform into a monster with four eyes and six long necks equipped with grisly heads, each of which contained three rows of sharp teeth. Her body consisted of 12 tentacle-like legs and a cat's tail, while four to six dog-heads ringed her waist. In this form, she attacked the ships of passing sailors, seizing one of the crew with each of her heads.
No ship that dares sail in her waters goes unscathed. Those that cling to survival whisper panicked tales of enormous black tentacles tipped with slavering hound heads ravaging whole ships to splinters with pitiless precision. Though it is her laughter, they say, that is most horrible; child-like, delighting in blood soaked murder as men are dragged into the dark abyss. Compared to Charybdis, who is a mindless beast, Scylla is merciless and consumed by hatred.