Francis Ford Coppola falls down and goes boom with this depressing, ill-conceived comedy. Jack Powers (Robin Williams) is big for his age -- really big. Because of a rare developmental disorder -- his biological clock ticks four times the normal rate -- ten-year-old Jack has a child's mind in a hairy 40-year-old's body. Of course he's teased at school, but the real threat comes from full-grown women. From his overprotective and frankly Oedipal mother (Diane Lane, whose youth is unnerving alongside Williams' middle age) to Dolores Durante (Fran Drescher), the mother of Jack's best friend and a woman so man-hungry that IQ's not a consideration, Jack's world is fraught with sexual tension. Williams remains mercifully understated throughout, and it's beautifully shot by Academy Award-winning cinematographer John Toll ( LEGENDS OF THE FALL, BRAVEHEART ), but it's difficult to imagine who the movie's intended audience might be. Though they'll enjoy a few gross-out scenes involving worm-eating and farting into a coffee can, children will only be puzzled by the film's libidinous humor and Jack's existential angst. (He's keenly aware of his accelerated mortality.) Adults -- at least the kind who don't work in Hollywood -- are likely to find the whole thing dreary and more than a little distasteful.