The Rhedosaurus 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. Attempts to kill it were complicated by an ancient disease it carried; spilling its blood freed the plague, which was almost as deadly as the reptile itself. 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.
The Rhedosaurus' blood contains a deadly germ that can enter the bodies of other organisms which cause severe sickness and eventually death.
- The Rhedosaurus, along with King Kong, was one of the main inspirations for Godzilla.
- The Rhedosaurus puppet was used again in the film Planet of Dinosaurs, where it was used as a Rhedosaurus that was killed by a Tyrannosaurus rex. Another Rhedosaurus made a cameo in When Dinosaurs Ruled the Earth, a film from 1970.
- The Rhedosaurus appeared in the 6th episode of the 2nd season of ABC's Whose Line Is It Anyway?.