Mr.Gray is an underrated antagonist in Stephen King’s lineup of crazy villains in my opinion. Mr.Gray is a type of Alien called a Ripley or Byrum in the original novel, that is like a lamprey in shape, with a massive set of jaws that makeup half his body only stopping at his torso. He is equipped with a tri-pincer tail which can work also as a blade. He is capable of possession and can alter his form to appear more humanoid-like. He speaks in a very formal manner when he steals Jonsey’s body throughout most of the story, using him to sneak undetected across Maine and its revealed in the novel his motives for wanting to spread a fungal type of virus which produces more of his kind, and why he is so determined to slaughter mankind is because his planet was destroyed during an ongoing war which lasted years, and he sees colonization as a last ditch effort to ensure his kind’s future. These details were left out of the film adaptation which is a shame, however they did display him being a rouge and setting out to accomplish his goal on his own, rather than stay with what’s left of his people in the crash site up in the mountains like in the book