Jamie Kennedy ("Malibu's Most Wanted"), taking over the Mask mantle from Jim Carrey, has described his version of the character as "Jay Leno's chin, Bob's Big Boy hair, Green Giant color, big horse teeth. It's like the Hulk on weirdness." Looking at those words, one might think, Gosh, that doesn't sound funny.

And, indeed, "Son of the Mask" is not. It's a movie whose mania and mindlessness provide some considerable narrative oomph, at least for the younger set, but humor is not one of the results. It goes without saying that anyone trying to take over for the face-morphing Carrey is bound for trouble, as the amiable Kennedy is, but the real problem with this sequel to the 1994 hit is that it, like the Mask-powered baby in it that has the ability literally to bounce off walls, is all over the place.

The story: The mask that imbues any wearer with zaniness-to-the-zillionth is brought home by a dog to its master, struggling illustrator Tim Avery (Kennedy). He's married to successful marketing executive Tonya Avery (the pretty-as-peaches Traylor Howard, from TV's "Monk"), whose biological clock isn't just ticking--it's struck. Tim shies away from the idea of fatherhood--until, that is, it's thrust upon him, thanks to a night of wildness powered by his putting on the mask. And lo, born to them is a son, Alvey (Liam and Ryan Falconer), who, thanks to his mask-induced siring, has crazed energies that come to fruition during a week of daddy-care, driving Tim to the professional and personal edge. Meanwhile, Norse god of mischief Loki (Alan Cumming, in "Spy Kids" mode) is desperately seeking the mask, a creation of his that got loose and has him in the doghouse with no-nonsense dad Odin (an unrecognizable Bob Hoskins). Ultimately, Tim must do battle with Loki to save his son--a supposedly heartwarming bit of homily that makes this the family film its PG rating suggests.

Indeed, families with undemanding young children might find this a diverting way to spend part of an afternoon, as long as they don't mind unpersuasive special effects, narrative sloppiness (near film's end, the Averys' baby becomes normal, for no known reason), and shameless borrowings from the classic cartoon "One Froggy Evening" (a Looney Tune by animator Chuck Jones; it's uncertain why the family's surname references fellow Warner Bros. animator Tex Avery). Direction by Lawrence Guterman is as mundane as his was in "Cats & Dogs." At least screenwriter Lance Khazei (who scripted Nickelodeon cartoons "CatDog" and "Aaahh!!! Real Monsters") can claim the cover of being a newcomer to long-form features. Starring Jamie Kennedy, Alan Cumming, Traylor Howard and Bob Hoskins. Directed by Lawrence Guterman. Written by Lance Khazei. Produced by Erica Huggins and Scott Kroopf. A New Line release. Comedy. Rated PG for action, crude and suggestive humor and language. Running time: 95 min