I just read The Merciless by Danielle Vega. It's like the Plastics meet the Christian Jewels and the Bitches of Eastwick.
I don't mean this as a joke, or as a dig at the author. I enjoyed the book. I read it in one day.
It has the same feel of Mean Girls, in its discussion of boys, Burn Books, and well, girls who are mean. With its hot pink cover, it even looks like a Burn Book.
It has the born-again Christian bent of Saved, with the group of girls attempting to perform an exorcism on a schoolmate.
But when the stunt gets out of hand, they begin to turn on each other with the power of four pissed off witches.
These three movies were popular with teen girls (and are probably still watched by some 30 something women) because they depict various aspects of female friendship, or rather, frenemy relations.
In each story, there is a girl who's Other. Maybe not in the beginning, maybe not the entire time, but at some point she grows uncomfortable with the actions of the other girls, which precedes the crumbling of their power structure.
Obviously this book won't satisfy hard core horror fans, but for readers who enjoy the kind of horror akin to Pretty Little Liars, it's a good fit. And just like any good horror story- there IS a twist at the end.
It's so fetch.