Tim Allen plays Deputy D.A. Dave Douglas, whose high-maintenance career keeps him alienated from his wife Rebecca (Kristen Davis) and kids Josh and Carly (Spencer Breslin and Zena Grey). And wouldn't you know it, Dave's boss (Danny Glover) wants him to become the new district attorney. Dave's latest case involves one of Carly's teachers, arrested for setting fire to an animal-experimentation lab. The teacher claims the lab is conducting secret experiments and, as it turns out, he's right. The facility is run by the evil Dr. Kozak (poor, poor Robert Downey Jr.) who has kidnapped a 300-year-old bearded collie whose blood may hold the key to an anti-aging serum. Kozak has been testing the serum on various animals, creating creepy hybrids like a snake with a furry tail and some sort of bulldog/frog combination (presumably a bullfrog).
The age-defying mutt escapes and winds up in the Douglas household, where he bites Dave on the hand. Within hours, he's scratching behind his ears and sleeping on the foot of his bed. These moments, with Dave succumbing to his animal instincts by shredding court papers with his teeth and licking breakfast cereal out of the bowl, are the film's workable approximation of comedy (had Dave humped his wife from behind, then we'd really be getting somewhere). Soon Dave becomes 100 percent dog, which makes it hard to prosecute his case. But it makes it easy to eavesdrop on his children. Hanging out with the dog under the justifiable assumption that dad isn't around, Josh reveals his dream of dancing in the school play while Carly starts fooling around with boys.
From a lessons-learned standpoint, Dave overhearing his children complain about his parental shortcomings certainly works. Better parenting through science. But the movie loses traction when Dave is a full-blown dog. It involves Allen in voiceover, which sounds unnatural and constricts the comedy to shots of a cute dog doing cute things. And most of the dog scenes have Dave either interacting with his family or trying to thwart Dr. Kozak's plan, neither of which are funny or interesting.
Allen, upon whose furry shoulders the whole enterprise rests, is game in a broadly comedic sense. But the film's best asset, and biggest missed opportunity, is its supporting cast. Glover, Downey Jr. and Philip Baker Hall (as Kozak's wheelchair-bound boss) are underutilized and give off the dull shine of terrific actors whose phones don't ring as much anymore and are willing to take anything high-profile.
"The Shaggy Dog" has a kid-appropriate level of energy, some parent-approved speechifying and a couple of mild laughs. But it's a benignly bad creation, directed with one hand wrapped around the bullhorn and the other around a low-fat latte. The childhood affection we hold for vintage live-action Disney movies deserves better. Starring Tim Allen, Robert Downey Jr., Kristen Davis and Danny Glover. Directed by Brian Robbins. Written by The Wibberlys and Geoff Rodkey and Jack Amiel & Michael Begler. Produced by David Hoberman and Tim Allen. A Buena Vista release. Comedy. Rated PG for some mild rude humor. Running time: 92 min