Zilla

Zilla (ジラ) is Toho Studio's official name for the titular creature of the 1998 American film. Zilla is a giant mutated 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. Its irradiated genes caused it to achieve a height of over sixty meters (about two-hundred feet).