The Rhedosaurus in the film was one of the last surviving members of its species, awakened by a nuclear weapons 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. For example, Godzilla's title during developments was actually Daikaijū from 20,000 Miles Under the Sea (海底二万哩から来た大怪獣) whose storyline was also similar; an ancient dinosaur wakes up by nuclear testing in Bikini Atoll and attacks Tokyo.
- Later the title was changed to Godzilla because Tomoyuki Tanaka felt it was too long. Ichirō Sato, a movie producer, introduced that Shirō Tsunakura, chief or Toho's theatrical club later, had been called "Gujira" for his "fondness of whale meats and his appearance recalling a gorilla", providing hints to Tanaka. Hiroshi Mukouyama later revealed that some actually thought "Godzilla" might sounds too weak in terms of giving an impression, and instead preferred "Godzillā".
- Some of earlier concepts of Godzilla include "a giant whale monster attacks Tokyo" and "a giant octopus appeared from Indian Ocean and attacks Japanese whaling ship".
- Originally, Rhedosaurus was planned to breath atomic flame from the mouth and this can be seen on earlier posters. Although, this was scrapped due to budgetary problems.
- Stephen Czerkas constructed a stop-motion Rhedosaurus model for the 1977 film Planet of Dinosaurs, where it battles and is killed by a Tyrannosaurus Rex. According to animator Jim Aupperle, "Stephen and I both place the Rhedosaurus among our top favourite of Ray's myriad monsters. We felt that by giving the great Beast a cameo in our film we were acknowledging the immense debt we both feel to Ray. We had to make the Rhedosaurus more of a baby size because one as large as the original would have made a meal of our Tyrannosaurus instead of the other way around."
- A creature resembling the Rhedosaurus briefly appeared in the 1970 film When Dinosaurs Ruled the Earth, though whether it is meant to be an homage to the Rhedosaurus is unclear.
- The Rhedosaurus appeared in the 6th episode of the 2nd season of ABC's Whose Line Is It Anyway?.