The Space Monsters (宇宙怪獣) are the main antagonists of Top o Nerae! Gunbuster and Top o Nerae! 2: Diebuster. There are several different types, ranging from large insectoid aliens to entire organic alien motherships. They feed off of the energy of stars, causing them to age rapidly and eventually supernova. Their nest is located in the Galactic Nucleus. In Top o Nerae! Gunbuster, they are described as the white blood cells of the galaxy, which see humanity as a virus.