Stephen King's work has been adapted into movies, miniseries, plays, comic books and more over the course of five decades, but it's rare for the man himself to take on the role of adapting his books into screenplays. So when King stopped by MTV News for a chat, we had to ask why "A Good Marriage," which hits theaters on October 3, stood out.

"It's a story that stuck with me, and I wanted another bite of that particular apple," King explained. "It's a story about a woman who discovers that the man that she's been married to for 25 years is essentially a stranger, with a monster inside."

King further clarified that the novella's length made it a much easier process, since he didn't have to worry about cutting out plot lines for the sake of a good film.

The story is the right length to adapt to screenplay without feeling like you have to jettison a lot of stuff," he said. "A lot of books are so crammed with incident and story that it's like a lifeboat that's going to sink if you don't throw some of the people overboard. I hate that, making those decisions."

Also, having Stephen King on board can certainly make for a more terrifying movie.

"It also gave me a chance to refine some of the things that were scary in the story," he concluded.