The Beast is a normal Rhedosaurus .
The Beast in the film was one of the last surviving members of its species, awakened by a nuclear test in the Arctic. It made its way down the North American coast, destroying everything in its path and ending up in New York, its original home.The Rhedosaurus was eventually killed at Coney Island when a radioactive isotope was shot into a wound on its neck, both fatally wounding it and also neutralizing the disease. As the Rhedosaurus succumbed to the isotope, a fire it started by destroying the machinery of a roller coaster spread across the island. The Rhedosaurus burst free of the burning coaster and roared out defiantly before finally collapsing to the ground dead.