Bad filmmaking meets bad science and bad philosophy in The Butterfly Effect, a science-fiction howler that suggests an entire season of a misbegotten Quantum Leap knockoff condensed into a seriously insane feature film. Just how crazy is The Butterfly Effect? Put it this way: The casting of Punk'd enthusiast Ashton Kutcher as a dark, tormented genius actually qualifies as one of its more plausible elements. Kutcher doesn't even figure prominently in most of the film's first act, which recounts its protagonist's tortured upbringing in a not-so-idyllic small town whose chief industry seems to be manufacturing childhood trauma. Eventually, that protagonist grows up to be Kutcher, a science geek investigating the formative crises of his youth as a way of explaining his own fractured psyche. A love story between Kutcher and Amy Smart ostensibly anchors the film, but instead of the traditional boy-gets-girl, boy-loses-girl, boy-gets-girl-back arc, Butterfly Effect lays out a plot in which boy meets girl, falls for her, accidentally kills her, unkills her, and encounters an alternate reality in which she's a beaten-up junkie whore. (Not necessarily in that order.) Butterfly Effect skitters restlessly back and forth through alternate realities like the Cliffs Notes version of Slaughterhouse-Five, in the process affording its cast an opportunity to adopt and discard a slew of different personalities and identities. Fans of Kutcher, from little girls to prominent gay sex-advice columnists, will be delighted to find that there are actually something like half a dozen different Ashton Kutchers in the film's alternate realities, all of them thinly conceived and unconvincing. There's the "Where's the rest of me?" amputee Kutcher, frat boy Kutcher, an unkempt Kutcher who looks like the hirsute love child of Jack Black and Charles Manson, and, most memorably, jailhouse Kutcher, who spends time in a prison where getting punk'd doesn't involve celebrity pranks. It's hard not to like a film in which an overhyped pretty boy offers to perform oral sex on a muscle-bound neo-Nazi convict, or in which gifted young character actor Elden Henson gets to play both his usual troubled misfit and a long-haired hunk who out-dreamboats Kutcher to win Smart's heart. (The romance-novel version of Henson is a little like Philip Seymour Hoffman playing Fabio.) Those are just two of the many reasons The Butterfly Effect is a bad-movie-lover's heaven, and a good-movie-lover's hell.