Sub-Basement Cat is the ultimate evil behind everything, and exists only to make every other living being suffer. Sub-Basement Cat is capable of ending the world as we know it. The UnUniverse could be completely destroyed by Sub-Basement Cat. The only thing stopping Sub-Basement Cat from ending the UnUniverse is the popularity of the Lolcat meme. The less popular the meme is, the more powerful Sub-Basement Cat becomes. Sub-Basement Cat was almost completely hidden from us until all of these low-quality "MLG" memes started popping up around 2011.
Sub-Basement Cat appeared long before time itself and spent all of its time causing death, suffering, and terror. Many have suffered because of Sub-Basement Cat, and he will show no mercy if the UnUniverse was ever to fall into his grasp.
There is next to no information about Sub-Basement Cat, but what does remain states that he has power equal to Ceiling Cat himself. There is little to nothing you can do if Sub-Basement Cat wants to destroy you. Legends say he was the one who created Ybatpng, which is an evil clone of Longcat that is a lot worse than Tacgnol.