GET READY for a rather strong audience reaction when Megan Fox slides her tongue into costar Amanda Seyfried's mouth in Jennifer's Body. However! While hot teen bisexualism might be a cheap (and hot) way to sell a horror flick, this time there's a deeper message to be found.

Fox plays Jennifer, a high school hottie in the small town of Devil's Kettle who, while wildly popular, continues to be BFFs with her nebbish childhood buddy, the aptly named Needy (Seyfried). Jennifer and Needy have a complicated and symbiotic relationship: Needy needs Jennifer to feel accepted, while Jennifer needs Needy to endure her subtle put-downs and raise her flagging self-esteem. But things get even more complicated when the members of Low Shoulder, a struggling emo band with an interest in the occult (not joking!) and a lead singer played by the hilarious Adam Brody (Seth from The O.C.—not joking!), accidentally turn Jennifer into an intestines-devouring demon. As the newly demonized Jennifer feeds on the horny teenage boys of Devil's Kettle, the town is brought to its knees—and all of Jennifer and Needy's relationship issues bubble up to the surface. One of which, thankfully, is suppressed lesbianism.

First of all, don't go into Jennifer's Body expecting Drag Me to Hell. Jennifer's Body director Karyn Kusama is no Sam Raimi, and be glad of it. (If she were, we'd have a toothless Megan Fox gumming on Amanda Seyfried's chin. Gross.) Jennifer's Body is more of a mainstream product—but in the best possible way. It's smart, creepy, funny, thoughtful, disgusting, and, for a horror movie, surprisingly pro-woman. And it works because all the pieces fit perfectly together.

While screenwriter Diablo Cody has been accused of being overly precious (for proof, see the overly precious Juno), here her cleverly worded script is streamlined to fit into the slash 'n' sex genre of horror. While the quips come fast, funny, and furious, it never slows down the plot or Kusama's thoughtful direction, which often reveals the underlying truths behind Cody's deceptively glib teen-speak.

Acting-wise, Amanda Seyfried is terrifically believable as the nerd who's forced to turn warrior, and as for Megan Fox—what can I say? She's kind of perfect. As a generally unlikeable person in real life, Fox's general unlikeableness works like a charm here. Still, while Jennifer's face and body are stunningly distracting, it's easy to see why she might have esteem issues—even when she's eating a football player's lower intestine. And when her tongue creeps into Needy's mouth, you know that it isn't just the demon talking. It's shorthand for the fact that, as Cody puts it, "Hell is a teenage girl."