[@Dead Cruiser] I wrote out kind of the rough draft of its backstory, but thats basically the barebones idea of the Arc for it that I had, if this doesnt fit to what you were looking for, i can totally come up with a new idea entirely

[hider=The Summary of the Backstory is a bit long, sorry!]The Slime was an accidental creation after the Gods of It's Universe attempted to create a space in which would be a trash can of sorts for their failed or unwanted experiments. The Slime's arc is essentially that it was treated as a tool by the Gods, until the Youngest God, one that was upset with their current position amongst the gods, saw the slime as a potential means of boosting their ranking amongst their kind. Befriending the slime in secret, the Young God eventually tricked the It into absorbing the pocket dimension that kept it contained, increasing its power ubsurdly and freeing it. The Young God then used the slimes newfound desire to absorb and learn new things against it, tricking it into decimating entire planets and populations, and leaving a barren wasteland anywhere the Young God dropped it. 

Eventually, after absorbing 25% of the universe, the Gods sent one of themselves to investigate the Slime, only for the Slime to completely absorb the pure energy of a God. This both vastly shifted the Slime and Young Gods motive, the prior becoming intoxicated with its desire and the latter realizing their mistake in creating a god killing being who was becoming uncontrollable. The gods attempted to unify the universe in a war against the slime, but after absorbing the power of a god, it became an unstoppable force. With the universe unintendedly sending fleets and powerful beings to confront the Slime on a silver platter so to speak, the Slime absorbed nearly 75% of the universe before the Gods intervened directly. 

Confronting the Slime in hundreds, the Gods stepped right into the Slime's trap, as it had created thousands of itself, and forced the 8 oldest gods to hide themselves away into a pocket dimension. There they decided the only way to fix their problem was to reset the universe and start a new again. However after absorbing the Youngest God, with the combined power of the all gods but 8, it was able to break into the pocket dimension and begin absorbing the Old Gods. All until three remained, combining themselves and their power into one final explosion that would have erases their universe from existance as the Slime began to absorb them. They did succeed in destroying their universe, however absorbing the remaining Gods power caused the Slime to ascended to that of a being higher then the gods of It's universe. It's body using this newfound power, seperated It from the collapsing universe into the Void, the space between universes, where it began the slow process of evolving into an Ascended Slime.[/hider]