Hercules and the princess Hesione fight a vicious, odd-looking sea monster on a 13-inch-high, sixth-century B.C. Greek vase (see detail) now in the Museum of Fine Arts, Boston. So unusual is the monster, in fact, that author Adrienne Mayor suggests it was modeled on the skull of an extinct creature. According to Greek myth, when a sea monster known as the Monster of Troy begins to ravage the Trojan coast, King Laomedon sends his daughter, Hesione, as a sacrifice. Hesione is rescued by Hercules, and the two then kill the monster. Art historians have long puzzled over the strange physiognomy of the monster on this Corinthian vase. Was it simply badly drawn? Was it supposed to be funny? Or was it, as Mayor argues, drawn after the fossilized bones of a creature washed out from a hillside? One thing we know for sure: The ancient Greeks were fascinated by huge fossils, which they sometimes thought were the remains of mythical heroes.