20th Century Fox

A fiery end to a local watering hole leaves Jennifer (Megan Fox) nonplussed.

There's one thing that can be learned from "Jennifer's Body," the kitschy high-school horror/girl power flick written by Diablo Cody ("Juno") and directed by Karyn Kusama ("Girlfight"): Never, ever trust a lame indie-rock band.

When Jennifer (Megan Fox), the hottest girl at small-town Devil's Kettle High, drags along her geeky best friend Needy (Amanda Seyfried) to see the guyliner group Low Shoulder with the intention of entertaining them after the show, little did she know that they'd end up possessing her with a demon. Sure beats trashing hotel rooms.

Jennifer now hungers for the taste of teenage testosterone and, faster than you can say "emo," she's chomping on every young guy at Devil's Kettle like a Hot Pocket. The only one who might be able to stop her killing spree is Needy.

It's a fun premise -- a twist on the usual girl-in-distress scenario of the standard-issue horror film -- enlivened by Codyspeak, the hipster, pop-culture saturated lingo the screenwriter showed off in "Juno."

Fox gets to show off as well, with one thing for which she's known (skin) and one she's not (more acting range than in "Transformers," but then that's not saying much). Plus, there are some notable, if underused, secondary characters -- J.K. Simmons as a straight-laced teacher, Amy Sedaris as Needy's mom.

But, for a film that's supposed to be both scary and funny, it's not really either most of the time. And Kusama's languid direction lacks the kineticism that might've given it a kick; at 102 minutes, "Jennifer's Body" is far too long -- a movie like this shouldn't clock in at a second over 90, tops.

Still, the film's larger lesson holds. If you see a band coming into your town that's like an unholy union between a third-rate version of the group Train and a fifth-rate version of The Killers, be very, very afraid.