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?
Anita "Needy" Lesnicki (Amanda Seyfried), once an insecure teenager, is now a violent mental inmate who narrates the story as a flashback while in solitary confinement. She has been friends with a selfish and popular cheerleader, Jennifer Check (Megan Fox), since childhood, despite having little in common. One night, Jennifer takes Needy to a local dive bar to attend a concert by indie rock band Low Shoulder. A suspicious fire engulfs the bar, killing several, and Jennifer who is in shock, agrees to leave with the band despite Needy's attempts to stop her. Later that evening, Jennifer, covered in blood, appears in Needy's kitchen and proceeds to eat food from the refrigerator. Unable to digest the matter, she vomits a trail of black, spiny fluid and then leaves in a hurry as Needy calls after her.
The next morning at school, Jennifer appears fine and shrugs off Needy's concerns. While the small town is devastated by the deaths caused by the fire, Jennifer seduces the school's football captain in the woods and then attacks him; his disemboweled corpse is later found. Meanwhile, the members of Low Shoulder gain popularity due to their rumored heroism during the fire and offer to make a charity appearance at the school's spring formal.
A month later, Jennifer is beginning to look pale, and accepts a date with school goth/emo Colin (Kyle Gallner), whom she brutally kills that night. While Needy and her boyfriend, Chip (Johnny Simmons) have sex, Needy senses something dreadful has happened. She leaves in a panic and almost runs over Jennifer, drenched in blood. She rushes home and finds Jennifer in her bedroom. Jennifer kisses her, initiating a brief makeout session, and soon explains what happened after the fire: Low Shoulder took her into the woods and offered her as a virgin sacrifice to Satan in exchange for fame and fortune. Although the sacrifice and greedy exchange were a success, Jennifer was in fact not a virgin, and when the lead singer Nikolai (Adam Brody) murdered her, the ritual backfired and a demonic spirit took over her body. Unbeknownst to Needy, Jennifer also encountered the Indian exchange student Ahmet after the fire and, upon hearing that no one knew he had survived, took him into the woods and ate him, rendering him her first victim. Jennifer states that she can withstand virtually any injury without pain and is rather difficult to kill.
The next day at school, as the town is stunned by Colin's death, Needy goes to the school library's occult section and surmises that Jennifer is a succubus; she is weakest when she is hungry, and must feed on flesh in order to sustain her life and appearance. Needy tells Chip about her discoveries and warns him not to attend the school dance. He does not believe her and she subsequently breaks up with him in order to protect him. Chip goes to the dance, hoping to meet with Needy, but is instead intercepted by Jennifer, who seduces him and takes him to an abandoned pool house. Needy arrives there and finds Jennifer feeding on Chip. Needy tries to drown Jennifer but Jennifer, hovering in the air, attacks her. She is then stabbed by Chip with a pool skimmer. Jennifer escapes while Needy watches her boyfriend die.
Needy decides she must kill Jennifer for the common good. She goes to Jennifer's home and sees Jennifer picking out her next victims in her yearbook. Crashing through the window, Needy engages in a fight with Jennifer wielding a box cutter. Culminating with a stab to the heart, Needy finally destroys the demon and kills her. Jennifer's mother enters and finds Needy with the box cutter on top of her daughter's body. Soon after, Needy is brought to an asylum. Since she was bitten non-fatally by Jennifer, she has obtained some of Jennifer's supernatural powers, such as the ability to hover in the air. Set upon revenge for what was done to Jennifer and her, she escapes the mental facility and hitchhikes a ride to the hotel where Low Shoulder are staying; there, she slaughters the members, whose killings are later discovered by local authorities.
The film was released on DVD and Blu-ray on December 29, 2009 in the USA and Canada. In Australia, the DVD and Blu-ray was released on May 18, 2010.The film opened at #11 at the DVD sales chart, making $1.6m in the first week off 104,000 DVD units.There is a rated and an unrated version, with the unrated version running about five minutes longer than the theatrical version. The UK Blu-ray lacks most of the extras found on the locked US release
- Jennifer and Needy were originally going to have a sex scene in the film.
- The "waterfall that goes nowhere" is the Devil's Kettle, at Judge Magney State Park in Minnesota. The water disappears into a glacial pothole.
- To prepare for her role as a possessed living-dead teenager, Megan Fox lost around 15 lbs, bringing her weight down to a near-frail 97 lbs, and stayed out of the sun.
- Jennifer's surname 'Check' was initially intended only to be a place holder name. It comes from writer Diablo Cody using the phrase 'check' to express the filling of the various required roles, e.g "Jennifer - check, Needy - check" and so on. The name was never changed and features in the final film.
- There was no makeout scene between Needy and Jennifer in the original script.
- The directors cut of the film was removed from Australian supermarkets due to the graphic sex scenes and the violence.
- The name 'Needy' Lesnicky comes from writer Diablo Cody's initial intention to have the character be of a 'needy' disposition. She later decided against this as she felt she had seen enough nerdy stereotypes in high school set movies.
- In the Melody Lane sequence. At first, you just see her holding a drink but later, when Jennifer says she'll score some alcohol by "playing Hello Titty with the bartender", the bartender who serves her turns out to be Cody.
- Colin invites Jennifer to "Rocky Horror at the Bijou," a reference to a student-run movie theater at the University of Iowa. Diablo Cody graduated from the University of Iowa.
- The demon who possesses Jennifer Check (Megan Fox's character) closely resembles a succubus (plural succubi), from Jewish, Christian, and Sumerian mythology/theology. It is said that succubi seduce men, and fornicate with them until they are "drained" (in the movie, getting "drained" could mean getting drained of blood instead of semen). Some possible examples of succubi are Lilitu (from Sumerian mythology), Lilin, and Lilith (both from Jewish theology).
- Promotional material for the movie was released up to 15 months before the release date.
- The band's name in the film was originally "Soft Shoulder" before being changed to "Low Shoulder."
- A Fall Out Boy poster is shown above Jennifer's bed before Needy enters the room to kill her.
- A few actors from Diablo Cody's Juno (2007) appear in Jennifer's Body (2009). J.K. Simmons, Valerie Tian and Aman Johal. The film is also co-produced by Juno (2007) director Jason Reitman.
- A draft of the script was leaked online in early 2008.
- The first poster was unveiled in July 2008, at the San Diego Comic-Con. It showed Jennifer licking a drop of blood from her lips.
- Grammy Award-winning Pop-Rock band Maroon 5 and their lead singer Adam Levine are referenced in the film once by Low Shoulder.
- "She's evil... and not just high school evil".
- When Nikolai is about to stab Jennifer, there is a distant shot where he says, "We have to make a really good impression on him," Jennifer isn't crying and her mouth is closed.
- When Jennifer is lighting her tongue with the lighter, her hair is front of her ear in distant shots, then behind her ear in the close-up.
- The first time Needy and Chip walk away from her locker, the shoulder straps of Chip's backpack jump from one shoulder on, to two, to one, to two again.
- Just after the fire in Needy's kitchen, Jennifer appears in profile, with a ghastly, toothy smile. In the next full-face shot, her mouth is closed, and the ghastly smile appears slowly.
- In the Melody Lane bar, Jennifer returns with a tray of the two "9-11" drinks. She says, "Tower 1 isn't full enough." The camera cuts away and when it cuts back "Tower 1" is more full (blue layer). The camera cuts away again, and when cutting back, "Tower 1" is back to it's previous lower level.
- When Jennifer is in the forest with Jonas, as she unzips her jacket, it can clearly be seen that she has no belly button, though it is shown in other scenes.
- After Melody Lane catches on fire and Needy and Jennifer are outside kneeling in the parking lot it is obvious that there are no lenses in Needy's classes as there is no reflection of the fire.
- Before Jennifer is stabbed, the right strap of Needy's dress is off her shoulder and damaged, while the left is intact and in place. When we see Needy's reaction, the straps are off both her shoulders. When Jennifer removes the pole and walks past Needy, the strap is back in place.
- When Chip is almost dead and out of the swimming pool, Needy yells to Jennifer. Her face is very dirty, but in the next shot her face is almost clean.
- Jennifer is killed by a utility knife with a snap-off blade that isn't thick, strong, or sharp enough to penetrate the rib cage. In real life it would cause some damage, but it would snap when it hit bone.