The two sea monsters known from Greek mythology who attacted ships of passing sailors are Scylla and...

In Greek mythology, Scylla was a monster that lived on one side of a narrow channel of water, opposite her counterpart Charybdis. The two sides of the strait were within an arrow's range of each other—so close that sailors attempting to avoid Charybdis would pass dangerously close to Scylla and vice versa. Scylla and Charybdis made their first appearance in Homer's Odyssey.