Which six-headed sea monster attacks sailors?

Scylla is the six-headed sea monster that attacks sailors in Homer’s Odyssey. She lives beside a narrow sea passage opposite Charybdis, a deadly whirlpool.

When Odysseus’s ship passes through the strait, Scylla reaches down with her six heads and seizes six of his companions—one sailor for each head. Odysseus is warned that he cannot save everyone, so he steers closer to Scylla rather than risk losing the entire ship to Charybdis. The episode presents a choice between two unavoidable dangers.

Homer’s Scylla is a terrifying, multi-headed creature with twelve feet and a barking, dog-like appearance. Later Greek and Roman traditions add a different origin story, describing Scylla as a beautiful nymph transformed into a monster through divine jealousy or magic. These later versions explain details that are not fully developed in Homer’s poem.

Scylla is often confused with Charybdis because the two monsters appear in the same episode. They are not interchangeable: Scylla attacks and removes sailors from the ship, while Charybdis swallows the sea in a destructive whirlpool. The phrase “between Scylla and Charybdis” now means facing two dangerous alternatives.