Scylla is a legendary sea monster in Greek Mythology and featured prominently in the Odyssey.
She is described as having the upper body a large beautiful woman. Her lower body however is that of six dog heads and a large sea serpent's tail. Many artists nowadays, depict Scylla or Scylla-like creatures as humanoids with a tentacled lower body similar to that of Ursula from the little mermaid, with each tentacle ending in some kind of sea serpent head or jaws. During Odysseus' Journey home, he encounters a the Strait of Messina with to paths. One of them leads to Charybdis, an extremely dangerous sea monster that swallows the sea and anything floating in it entirely and Scylla. Odysseus realizes that both monsters are bad news but it is better to sail past Scylla since she will likely kill a number of his crew while Charybdis would likely swallow his entire ship.