Jennifer's Body (2009)

Director: Karyn Kusama
Genre: Comedy | Horror | Thriller
Tagline: She's evil... and not just high school evil.
Starring: Megan Fox, Amanda Seyfried, Adam Brody and Johnny Simmons

Plot: A newly possessed cheerleader turns into a killer who specializes in offing her male classmates. Can her best friend put an end to the horror?

http://www.imdb.com/title/tt1131734/
http://en.wikipedia.org/wiki/Jennifer's_Body