Aetherium

Aetherium is a living super-galaxy, as well as G-Rex's weapon and main agent in Universe -1, created by Koopa.

Appearance
When in its true form, Aetherium resembles a massive version of the Messier 83 galaxy - It is thought that this form was taken on by Aetherium after obliterating the galaxy's dominant race along with it. Aetherium is composed of many trillions of stars, and glows with an incredible brightness that outshines any galaxy he comes close to. As such, Aetherium can be seen for thousands of years before he actually arrives.

Aetherium can also take on the form of a colossal sword. In this form, Aetherium is wielded by G-Rex to destroy whole universes at a time.

Regardless of whether Aetherium is in his true or blade form, Aetherium is approximately one quarter the size of G-Rex.

When in his true form, Aetherium can modify his size to allow himself to fight opponents at a closer level, and can also possess them after death, as he did to Godzilla. Possessed subjects' eyes glow brightly, and the subject will also exude purplish-black smoke with every breath.

History
TBA

Abilities

 * Size Change: In both his true and Blade Form, Aetherium is able to condense and compress his size. He can also rapidly increase in size in his true form if necessary.
 * Possession: Exclusively used in his true form, Aetherium is able to inhabit and possess the corpses of his enemies by entering through the deceased's orifices, most commonly their mouth or nose. Aetherium is able to effectively replicate the former opponent's mannerisms and abilities once inhabiting their body.
 * Blade Form: By compressing himself, Aetherium can take on his Blade Form. In this form, Aetherium is either wielded by G-Rex or can move on his own. Like in his true form, Aetherium can further condense his size so that he can hit progressively smaller targets.

Trivia

 * Alongside G-Rex, Aetherium was created by me after I had spent an hour looking up images of galaxies. Space fascinates me, and I thought the idea of a living galaxy would be pretty cool.
 * Aetherium is the second-most overpowered monster in my library.