In The Butterfly Effect, Ashton Kutcher wakes up in a dorm room and discovers that he's got a pair of stumps where his forearms used to be. ''What the f---!'' he exclaims, and if there's a piece of dialogue this year campier than that, I'd love to hear it. Kutcher doesn't sound upset, exactly; he sounds punk'd, as if he'd just found himself sleeping next to Bruce Willis or something.
''The Butterfly Effect'' is a chain-reaction thriller in which Kutcher keeps diving back into his past and altering some horrendous event (child sexual abuse, a dog set on fire, you get the picture), then shooting into the different future that results from it. He ends up, for a scene or two, as a frat boy, a disabled sad sack, and a prisoner surrounded by thick-chested Aryan rapists. (Talk about punk'd.) Yet nothing in the movie has much consequence, since Kutcher keeps skipping to a new reality before we can figure out what he's doing in the old one. It's like he's trapped in a ''Twilight Zone'' theme restaurant.
There's a good head trip nestled somewhere within the messy, sodden execution of ''The Butterfly Effect''; I kept wondering what a moody grunge technician like David Fincher would have done with it. But Kutcher is the wrong actor to anchor a psychological freak-out. Wearing a scruffy beard and an expression of lost-dog woe, he overacts to signify that he wants to be taken seriously. He may yet turn out to be a movie star, but not if he comes on like Eric Roberts' kid brother scrambling to measure up.