Zilla is the main antagonist in the 1998 film Godzilla, a minor antagonist in the TV animated series sequel Godzilla: The Series, a supporting antagonist in the 2004 film Godzilla: Final Wars, an a major antagonist turned anti-hero in the comic book Godzilla: Rulers of Earth.
Zilla is a giant mutate iguana originating from a nuclear test in French Polynesia. As the test was done in 1968, the creature (or perhaps species) grew over a period of approximately thirty years. His irradiated genes caused him to achieve a height of over sixty meters (about-two hundred feet).
He swam from the islands across the Pacific, attacking a Japanese freighter, and then stomped across Panama. From there he traveled up the American Eastern Seaboard, where he sank several American fishing boats.