Rodan (ラドン, Radon?) is a fictional Japanese mutated pterosaur introduced in Rodan, a 1956 release from Toho Studios, the company that produced the Godzilla series. Like Godzilla and Anguirus, he is designed after a type of prehistoric reptile (the Japanese name "Radon" is a contraction of "pteranodon"). Radon is usually referred to as "Rodan" in the United States, possibly to avoid confusion with the atomic element Radon; any time his name is written in English in Japan, it is written as Rodan. He is occasionally portrayed as a rival and enemy of Godzilla, but is usually depicted as one of Godzilla's allies, much like Anguirus. Rodan and Anguirus both started out as enemies of Godzilla, which explains the occasional enmity between the creatures and Godzilla himself on the rare occasion that they are pitted against one another.