"godzilla vs. gigan" (1972) had the (also known as nebula m space hunter and space hunter galaxy m) invade earth in order to escape their own dying planet, long plagued by pollution caused by its previous (and now long extinct) inhabitants, a species just like humans. using "action signal tapes" to control gigan and king ghidorah, the aliens had the two monsters demolish tokyo until they were challenged by godzilla and anguirus.