The Area 51 Mutations are two kaiju created by TriStar Pictures that first appeared in the Godzilla: The Series episode Area 51. They were the monsters that were kept in Area 51 after their creation due to the extensive nuclear testing done there in the 1950's.
Desert Lizard and Desert Rat Bios
Other mutations spawned by decades of underground nuclear testing, the lizard and six-legged desert rat mutations were at home in the underground Area 51 reserve for mutations. Along with other creatures, such as the Thorny Devil and Giant Armadillo, they were studied for beneficial uses for mankind. They are the only two Mutations that are shown to not have escaped during the events of the episode Area 51.