The enormous critical and commercial success of 1988's Who Framed Roger Rabbit? seemed to portend an exciting new era in which the boundaries between live action and animation would blur and contract in new and innovative ways. Unfortunately, Rabbit's promise has gone largely unfulfilled, as later attempts to recreate its winning alchemy (Cool World, Monkeybone) have been marked by paltry box-office receipts and scathing reviews. Co-directed and co-produced by the Farrelly brothers, Osmosis Jones attempts a far less ambitious visual blend, alternating live-action scenes of lazy, beer-swilling Bill Murray with animation depicting the complex world within his bloated, much-abused body. As perhaps befits a movie about a war between a man's biological components, Osmosis Jones feels like three different films battling for supremacy. Most promisingly, it's an intermittently clever satire re-imagining the human body as a dysfunctional urban wasteland lorded over by a complacent, entrenched mayor (a well-cast William Shatner) more concerned with preserving his popularity than his master's health. Less promisingly, Osmosis Jones is yet another morality tale about a perfectly fine single father (Murray) deemed negligent in the film's eyes because of his reluctance to participate in a symbolic act of self-sacrifice by taking his whiny, unpleasant daughter on a hike. Least promisingly, Osmosis Jones offers cinema's umpteenth pair of mismatched partners—swaggering renegade white blood cell Chris Rock and by-the-books cold pill David Hyde Pierce—who reluctantly team up to battle evil parasite Laurence Fishburne. This last plot takes up most of Osmosis Jones' running time, and though Rock manages a nice extended riff about growing up on the wrong side of the digestive tract, the film unfortunately plays its mismatched-partners plot relatively straight. Like the similarly frustrating Shrek, Osmosis Jones relegates many of its freshest, funniest gags to the margins, dotting its vividly imagined biological dystopia with amusing sight gags and clever wordplay. If only its forgettable central characters were as smart and inventive as its throwaway jokes, the film would be an unqualified success. Instead, it feels like the world's longest PSA for healthy living, exercise, and a balanced diet.