Scylla

Scylla was once a beautiful sea nymph. In one version, Circe transformed her out of jealousy; in another, Poseidon's wife Amphitrite poisoned the waters where Scylla bathed. She became a monstrous creature rooted to a cliff face — six long necks ending in fearsome heads, each with three rows of teeth, and twelve tentacle-like legs.

She dwelt in a cave high on a cliff in the Strait of Messina, directly opposite the whirlpool Charybdis. Ships that sailed too far from Scylla were sucked into Charybdis and destroyed entirely. Ships that stayed close to Scylla's cliff lost six men — one to each head — but the vessel survived.

When Odysseus passed through the strait, Circe advised him to sail closer to Scylla. Losing six men was better than losing the entire ship to Charybdis. Odysseus watched helplessly as Scylla snatched six of his crew from the deck and devoured them. He later called it the most pitiable sight he witnessed in all his wanderings.