The central question behind “Jennifer’s Body” is one that is raised in the back of every high school football bus after every away game. “Would you still do Megan Fox if you knew she was going to kill you afterwards?”

Jennifer (Megan Fox) prepares to feast on her best friend’s boyfriend, Chip (Johnny Simmons), in “Jennifer’s Body.” (Doane Gregory | Twentieth Century Fox)

And amid an eager chorus of pimple-faced nods, you might find one kid, a shrimpy future lawyer who probably has no business playing football in the first place, demanding a more specific situation. “Why would she kill me? Would it hurt? Would I be remembered as the biggest player who ever lived?” he asks.

And instead of answering with her traditional dead arm, screenwriter Diablo Cody, who previously answered the slumber party favorite “What would you do if you were impregnated by Michael Cera and had a hamburger phone?” sets up an equally plausible scenario:

Jennifer (Megan Fox) is a girl with more than her fair share of sexual liberation. She struts through her school’s hallway with the appropriate amount of flirty lip biting and exposed navel that we have come to expect from a teen movie hottie.

But when a struggling indie band (led by Adam Brody, who should refrain from singing in the future) sequesters her after a gig gone awry, Jennifer becomes host to a demon libido, which causes her to indiscriminately seduce every boy who is given a line to speak—and then eat them. For if Jennifer wants to keep her flawless skin, sparkling eyes, and status as “would-you-rather” queen, she will have to continue her sexy cannibalism or (gasp!) accept average looks.

We see all these unfold from the eyes of Needy (Amanda Seyfried, no longer a Mean Girl), through the lenses of her unfortunate glasses and unresolved feelings toward her nymphomaniac BFF. Witnessing Jennifer’s Jekyll-and-Hyde behavior causes Needy the prescribed amount of anxiety, but it’s hard to focus on that with Megan Fox standing right next to her.

From here onward, the movie settles into a pattern consisting of Jennifer taking off her shirt, people sneaking around old, creaky houses, and typical high-school soap-opera drama. But as many genres as the movie imitates, it doesn’t really get any of them right. The few suspenseful moments end predictably, the special effects (mostly of Megan Fox’s jaw unhinging with fitting screeches) don’t generate any shock, and the jokes that don’t come at the expense of indie-rock bands generally fall flat. There’s also a paranormal research montage that seems to be ripped frame for frame from “Twilight,” which I like to think is evidence of a connection between two of the worst movies in the past two years.

The dialogue in the movie is also pretty stale. Two years ago, everyone fell in love with snappy little Juno and her real-life counterpart Diablo Cody. And why not? She got Rainn Wilson to say, “Homeslice.” But in “Jennifer’s Body,” Cody’s hipster wordplay is practically a dialect. Everyone speaks it, but it’s only fresh when the adults (Amy Sedaris and J.K. Simmons—that’s right, there are only two) do it. Everyone else sounds like an obnoxious teenage girl simultaneously sounding too smart and too stupid for her own good.

The humor, horror and dialogue in “Jennifer’s Body” are so out of sync that the movie feels like a satire, though I don’t know what it’s a satire of. While the plot could either be a messy allegory of eating disorders or an expression of homoerotic jealousy between best friends, the real point is moot. No matter how bad a movie starring Megan Fox is, she’s still out of your league.