Gojira (also referred to as Avatar of Mo-Tel) is a massively over-sized Fire Gecko reported to exist in the Mojave Wasteland as of 2301.
Despite the established extinction of mutated geckos from both the Mojave Wasteland and Zion Canyon, numerous travelers, mercenaries and general reprobates from the Mojave have reported the existence of a gargantuan fire Gecko residing near the South Vegas ruins. While many survivors maintain that this is just another wasteland myth, rehabilitated cultists and survivors speak of an encounter with Gojira, often claiming that the creature spoke to them personally, swearing vengeance on the tunnelers for their heretical predation. Immediately following this exchange, most affected subjects allege blacking out in face of the creatures sheer power only to awake shortly thereafter a great distance from the site of the encounter. Due to established consistency in survivor reports, the existence of Gojira is considered by the Followers of the Apocalypse as "not totally impossible".
Gojira is the same unused creature in Fallout: New Vegas, originally created by one of the animators to terrorize Camp McCarran for fun.