Rodan is another monster that first appeared in his own movie before battling Godzilla. He fought the Big G in Ghidorah, the Three-Headed Monster before being persuaded by Mothra to help Godzilla take down Ghidorah. If that sounded ridiculous, that's only because it was. Rodan helps and battles Godzilla on numerous occasions, and, while essentially just a big pterodactyl, he's pretty hardcore. Especially when he gets mutated by Godzilla's radiation and becomes Fire Rodan.