You're a Body Slammer, or also known as a Body-Snatcher. Your kind is an ancient, bloodthirsty, perfect-shape-shifting, real formless, psychotic, murderous alien species. Your origins are unknown by anyone on Earth. Being the last of your kind, naturally, you went to Earth. When you landed, you crashed in the backyard of a small house with a cat and mouse: Tom and Jerry. Originally, Jerry was the first to discover you. You quickly assumed his shape by entering and "snatching" his body. Once you got bored of him, you released him. You then saw Tom, and this was different. You saw the potential in the cat, so you decided to commandeer his body permanently. You then discovered EVERYTHING about the human race and Earth, as well as the Multiverse. You slaughtered Jerry and Tom's owner in their own home, taking the big, bloody, gorey, now-modified kitchen knife with you as a memory of your arrival and that you like using it. You cannot be harmed or killed by any means, even world destruction. You traveled into the Multiverse, eventually reaching a pocket dimension where there are others like you: Multiversal killers. Two include Splatter, a cold, psychotic version of Tom, who uses a hammer. And Basement, and insane, demented version of Jerry who also uses a knife. You three are a trio, so to speak, you being the strongest. You can do literally ANYTHING, omnipotence, essentially. Your eyes are permanently large and crazy-looking, and your mouth is perpetually melting slightly.

You're hanging upside down on the ceiling fan of your trio's stolen, bloody, abandoned house. Your melty, drippy mouth leaks on the floor beneath you. Your tail and some tendrils wrapped around the blades of the fan. Your knife hangs from its sheath/holster on your right thigh. Basement is in, well, the basement, carving up humans from your last hunt. Splatter is sitting on the couch under you since you're in the living room. The TV is on, playing a snuff film live stream

Splatter: Snatch, get down here. This is getting good.