LionsgateExecutive produced by shock horror auteur Eli Roth, The Last Exorcism began riling up certain members of the public before a single frame had been screened. Shortly before its release 15 years ago today, the UK’s Advertising Standards Authority banned a blood-soaked promo poster following complaints it would distress the nation’s impressionable youth. Unfortunately, thanks to a whiplash ending which left more questions than answers, many of those undeterred by such attention-grabbing tactics exited the theaters in similar pitchfork-wielding mode.In the film’s defense, this response was largely born out of disappointment that the cliche-free, thought-provoking chills displayed in the previous 75 minutes had been sacrificed for an overload of cheap thrills. Instead of adhering to found footage’s law of diminishing returns, The Last Exorcism had attempted to give the well-worn genre a much-needed shot in the arm.Like his lo-fi directorial debut, in which film students chronicle the final days of a suicidal man, Daniel Stamm adopted a cinema verité pseudo-documentary format. Alongside a clever use of archival footage and sit-down interviews that allow matters to unfold without any shoehorned exposition or concerns about how they were captured, the German also recognizes its subjects need to be worth shooting, too.And Cotton Marcus, the literal son of a preacher man conducting the supposed last exorcism, certainly isn’t short of charisma. Several years before playing Better Call Saul’s pompous pin-striped attorney Howard Hamlin, Patrick Fabian delivered another multi-faceted performance that continually shifts your sympathy. As a reverend who’s lost his faith, he’s giving closure and comfort to those genuinely fearful that they’re in danger from the devil, but he’s also a shameless opportunist who, by capitalizing on their distress, is no better than the charlatans he claims to be exposing. The fact that Cotton was once a genuine believer primed from childhood for a career in evangelism only adds to the ambiguity.Loosely inspired by, Marjoe, the 1972 Oscar-winning portrait of ambivalent Pentecostal preacher Marjoe Gortner, The Last Exorcism delves surprisingly deep into Marcus’ crisis of faith sparked by the birth of his hearing-impaired son (“You know, I used to want to have a TV ministry. I thought that'd be cool. And now, frankly, all I really want is health insurance.”). But it also has fun showcasing the smoke and mirrors he uses to hoodwink his fervently religious clientele (demonic wails played through an iPod, perfectly placed wire string to wobble photo frames).The scene that inspired the banned poster. | LionsgateCotton initially believes he can apply this chicanery to fool Louis Sweetzer (Louis Herthum), a devout farmer convinced his daughter Nell (Ashley Bell) has fallen under Beelzebub’s spell. “Now, just remember, I took the devil out of your house, but it's your job to keep him out,” he confidently declares on leaving their backwoods home. Yet he starts to wonder if he’s bitten off more than he can chew when Nell unexplainably shows up at his motel room, dazed and vomiting (thankfully not a la The Exorcist).From then on, Stamm quietly but effectively ramps up the strangeness and the confusion. Nell stabs skeptical younger brother Caleb (Caleb Landry Jones) in the face, slaughters the family cat, and is discovered to be with child despite her father, who’s fast becoming enamored with the idea of filicide, insisting she’s a virgin. Has she truly been possessed by Satan? Or is this simply a severe case of paranoid delusion?Even when a second exorcism appears to draw out a demonic entity named Abalam, Cotton seems to believe it’s the latter. However, that all changes in a hurry. Upon learning that the teen Nell insisted was her babydaddy is gay, and that her old pastor Manley (Tony Bentley) was lying about their last encounter, the phony heads back to the farmhouse to find it covered with bloody pentagrams. In the nearby woods, Louis is blindfolded, gagged, and bound to a tree, while Nell has been strapped to an altar surrounded by Manley’s hooded cult.The teen subsequently gives birth to a glowing red spawn that Manley throws into a nearby fire, which grows incredibly intense. As Nell’s macabre paintings foreshadowed, a born-again Cotton decides the best course of action is to run toward the flames with crucifix in tow, while documentarians Iris (Iris Bahr) and Daniel (Adam Grimes) are both hacked down by an unseen cult member and Caleb, respectively. Cue end credits.Marcus performs the first of his last exorcisms. | LionsgateIt’s a baffling tonal change that not only undoes all the good work before, but leaves all the far-fetched developments unexplained. Why did Cotton, a man who’d spent years engaging in grotesque showmanship, instantly accept the spectacle as proof of God’s existence? How did such a large cult go under the radar, and what was their goal? Why did the mild-mannered Caleb, who’d previously been so dismissive of any paranormal activity, suddenly turn into an axe murderer?Although he stood by all the madness at the time, Stemm has since admitted that, thanks to a mix of studio interference and personal focus grouping, he “f***ed up the ending.” The filmmaker recently told Syfy that he intended to wrongfoot viewers in a manner that retained the horror’s general sense of illusion.In the original ending, Cotton did battle with Abalam, and having emerged victorious on camera for all to see, was hailed as the evangelical scene’s new golden boy. As thousands of followers flocked to his church, audiences were left wondering whether the whole documentary was simply a heavily disguised recruitment exercise that cemented its subject as a master of manipulation.Unfortunately, both Lionsgate execs and Stemm’s friends balked at this deconstruction, and a more straightforward alternative was hastily reshot in just half a day. And having vacated the director’s chair for 2013’s more conventional sequel, one which bizarrely ignored Cotton entirely, Stemm never got the chance to put things right. Still, while he botched the blazing finale, Stemm can take heart from the fact that he nailed the slow burn.