Scylla

Scylla was the infamous sea monster who devoured sailors as they passed through the Strait of Messina. She had earlier been a beautiful nymph of variously recorded parentage, but Circe (out of envy of all the suitors she attracted) turned her into a monster with a woman's head and six dogs for legs - or something on similar lines, depending which account one reads or prefers. She lay low on a promontory opposite a whirlpool called Gharybdis (which see) - hence the phrase 'between Scylla and Charybdis' to refer to an unpleasant dilemma.

She was said to bark like a dog or whine like a puppy, and thus her name may mean 'whelp', 'puppy' (scymnos). However, she also used to tear her prey to pieces, and this suggests an origin in scyllo, 'to flay', 'rend'. Another Scylla was the daughter of Nisus, king of Megara, who has sometimes been confused with the monster.

Yet she did some 'rending' too, for she is said to have torn her father's body to pieces after she had caused his death by cutting off the golden hair on his head that ensured he would live. (In his Art of Love, Ovid positively identifies the monster with this second Scylla.)