[Lee Stewart]

Sea scorpions, or eurypterids, were a group of ocean-dwelling arthropods that resembled modern-day scorpions. What made them strange? Well, some were enormous compared with scorpions living today. For example, one eurypterid fossil found in New York is estimated to have come from a sea scorpion larger than a human. Members of this group could exceed 8 feet (2.5 m) in length, according to the Yale Peabody Museum of Natural History in Connecticut. Sea scorpions terrorized the seas for more than 200 million years, until they went extinct at the end of the Permian period (298.9 million to 251.9 million years ago).