In Greek mythology, the six-headed sea monster lurking on one side of the Strait of Messina is Scylla.
Scylla appears opposite Charybdis, the sea-swallowing monster, in Homer’s Odyssey. The two dangers were positioned so close together that sailors could not avoid one without nearing the other. Odysseus followed Circe’s advice to pass closer to Scylla, sacrificing six sailors rather than risk losing his entire ship in Charybdis’s whirlpool.
Descriptions vary across ancient sources and later art. Homer presents Scylla as a cliff-dwelling predator with six long necks and heads, each capable of snatching a sailor. Later traditions portray her as a transformed nymph with dog heads around her body, sometimes combined with serpent or fish-like features.
Scylla is commonly confused with Charybdis because the pair are usually mentioned together. The phrase “between Scylla and Charybdis” survives in English for a choice between two dangerous alternatives. The town of Scilla in Calabria is traditionally associated with her side of the strait.