Starring Craig Bierko, Anna Faris, and Regina Hall. Rated 14A.

The prevailing wisdom about juvenile, shticky comedies like Scary Movie 4 is that although the humour may be extremely gross, the teenage-male target will eat it up. But there are moments in this, the self-described fourth and final installment in the Scary Movie "trilogy", when even the adolescents will be left scratching their heads. After the mildly entertaining Scary Movie (2000), director Keenen Ivory Wayans came back for a lacklustre sequel in 2001, then left before 2003's return to form with Scary Movie 3, directed by old hand David Zucker, who is back for number four. In the wake of their 1977 stoner cult hit, The Kentucky Fried Movie, the team of Zucker, his brother Jerry, and Jim Abrahams was among the pioneers of the genre parody, with hits like Airplane, Top Secret, and the popular Naked Gun series. Written by Craig Mazin (with Abrahams), Scary Movie 4's Saw-inspired opening is promising enough, with Dr. Phil McGraw and Shaquille O'Neal chained in a grimy white-tile dungeon and engaging in a timidly funny parody of pop psychobabble. The action moves to a Japanese-style house, where Cindy Campbell, played once more by Anna Faris, channels Sarah Michelle Gellar in The Grudge. After the Viagra- related death of her husband (Charlie Sheen), Cindy moves in next door to Tom Ryan, played with good- natured cluelessness by Craig Bierko. As it turns out, her neighbour has his own date with disaster in the form of War of the Worlds-like alien Tr-iPods. It all goes downhill from there, when Campbell and her sex-addict girlfriend, Brenda (a hyperactive Regina Hall), end up in something resembling M. Night Shyamalan's The Village, where the puerile gags just keep on coming.

U.S. Secretary of State Condoleezza Rice recently commented that we shouldn't try to judge present events because we can never know how they'll be viewed in the future. Using that logic, one might speculate that Scary Movie 4, replete with topical references to Million Dollar Baby, Brokeback Mountain, and Tom Cruise's Oprah meltdown, might be viewed, someday, as a useful time capsule of the year 2005. But for now, Scary Movie 4 seems little more than an ill-conceived quagmire of lowbrow comedy and a stain on Zucker's film legacy. Then again, one should never underestimate that teenage-male demographic target.