Director Barry Levinson repeatedly plumbs the depths of implausibility in Envy, fishing for laughs but dredging up comedy deadweight instead. The enticing combo of Ben Stiller and Jack Black is simply not enough to boost this twisted morality tale about a friendship strained by a sudden imbalance in wealth. The differing styles of the two comedians never meld, but the script is so flabby even an industrial crane couldn't lift it.

Things get off to a plodding start as we're introduced to Tim Dingman (Stiller), a conscientious worker happy to climb the ladder to corporate success step-by-step. Black plays his best friend and neighbour Nick Vanderpark, a daydreamer who comes up with the screwball notion of a spray that vaporises doggy doo. Appalled, Tim passes up on the chance to invest and, inevitably, comes to regret it as "Vapoorizer" sweeps the globe and Nick builds his own Xanadu across the street.

"ENVY IS ALL ABOUT FLOGGING A DEAD HORSE"

Actually, it turns out that Black is short-changed by a deal that sees him having to play a character so gosh-darn nice it's insufferable. Levinson and screenwriter Steve Adams demonstrate a profound misunderstanding of the actor's appeal by eliminating the dark edge that makes Jack 'Black'. Meanwhile Stiller is called upon to do his usual uptight 'everyman' routine, but without conviction - little wonder given this hare-brained set-up.

Leaving aside the absurdity of disappearing dog poop, the narrative takes a fatal turn when Tim accidentally shoots Nick's prized pony and goes to extraordinary (and unfunny) lengths to conceal the body. An incident that should remain incidental becomes the major focus and dilutes the story's premise. The only source of amusement is the intrinsically quirky Christopher Walken as J-Man, the philosophising hobo who helps ditch the deceased animal. In every other aspect, Envy is all about flogging a dead horse.