Marlene King is leaving Rosewood -- but don't worry, the move is only temporary. The "Pretty Little Liars" boss is taking on the film adaptation of Danielle Vega’s teen horror novel "The Merciless," and according to her latest Instagram, she's already begun penning the "sick" and "twisted" script.

"The Merciless" tells the story of Sofia, a girl who falls in with a group of popular -- and devoutly religious -- girls during her first week at her new school. She quickly finds herself wrapped up in their plan to kidnap punky, alternagirl Brooklyn Stevens and exorcise the demon they know is living inside of her skin. It's pretty gruesome, and things obviously go wrong, fast. Yikes. This is too crazy for even "A"!

With "Pretty Little Liars" currently on hiatus, MarMar has plenty of time to think about bringing "The Merciless" to life, and she might even draw some inspiration from "PLL." Sure, the Liars aren't part of the occult, but there are some interesting parallels between the two projects.

There's similar tales of female friendship.

Similar to "Pretty Little Liars," "The Merciless" is a female ensemble story -- King says she has two "PLL" actresses in mind for the cast -- and there is a Big Bad that will haunt your worst nightmares.

It's scary AF.

One of best elements of "Pretty Little Liars" is its scare factor, and King is a master at building suspense. With "The Merciless," one event (spoiler alert: there's an exorcism) triggers the horror and never quite lets up. Prepare to be terrified and mildly disgusted.

It's extremely fast-paced.

"Pretty Little Liars" never dwells on one plotline for very long -- remember when Ezra was "A"? LOL -- unless, of course, you want to know who "A" is. Then, you'd have better luck actually exorcizing a demon from your frenemy's body. "The Merciless" is very similar. It's a fast-paced thrill-ride that doesn't spend a lot of time building up its characters but is enjoyable nonetheless because of its insane plot twists.