Bad Grandpa, a Jackass-branded candid-camera stunt comedy, is a movie that demonstrates that some spontaneous caught looks of shocked civilian outrage are a lot funnier than others. Johnny Knoxville, hidden under a deftly authentic senior-citizen makeup job (liver spots, salty mustache, thinning white hair combed back), pretends to be a cantankerous old coot named Irving, who after the death of his wife (a happy event, in his eyes) drives across America with his grandson, Billy (Jackson Nicoll), going into bars and bingo parlors and supermarkets, saying the most rudely inappropriate things he can. He propositions women with raunchy bluntness, or has Billy do it for him. He gets his member stuck in a soda machine, stops a car wash when an airbag goes off in his face, and generally behaves like someone who has just escaped from the senior center and has lost his marbles (though not his testicles; they, or at least an outrageous prosthetic version of them, are on full display).
Knoxville fires off some good lines (''I might be too old to stir the gravy, but I can still lick the spoon!'' he tells one female ''prospect''). But the character, once you get used to him (which takes about two minutes), isn't some wildly inspired comic creation. Knoxville doesn't have enough fun with the voice, and the truth is he's not really a very convincing old man. The one consistent joke of Bad Grandpa ''consistent,'' in this case, being a nice word for ''repetitive'' are the looks on the faces of the innocents he's punking. Their reactions are obviously genuine, and they tend to be mildly pop-eyed but polite and even, on occasion, openly amused (as with the woman who cracks up every time Irving takes another greedy swig of liquid blue bingo-board paste). Occasionally, someone gets truly steamed, like the lunk in a parking lot who screams at Irving after he destroys a giant plastic chicken mascot. But mostly, he's shrugged off as harmless.
In the Jackass films, the outraged looks tended to be on the faces of the audience. It was impossible to guess what depraved, nauseating, or infantile body-mauling ritual Knoxille and his boys were going to spring on you next, and that gave the movies, like the MTV series, a creatively funny, one-atrocity-after-another quality. Bad Grandpa, by contrast, has a same-thing-over-and-over quality, even though that one thing is amusing enough. The film presents itself as a comedy of danger, but thinking back on the sorts of button-pushing antics that Sacha Baron Cohen sprung in Borat and Bruno, he goaded and manipulated the victims of his pranks with a lot more abusive daring.
Bad Grandpa does have a handful of hilarious set pieces. A corpse falling out of a casket is always good for a big laugh, and when Irving stages his own private farting contest in the back booth of a diner, the explosive climax is as shocking to us as it is to the patrons (the rare moment in the movie when that's true). One of the high points has Irving going into a bar that's been turned, for an evening, into an impromptu female strip joint (yes, he gets up and performs). And at the end, when the grandson, in drag, enters a little-girl beauty contest, the movie far outdoes the crowning moment of Little Miss Sunshine. But most of Bad Grandpa lacks that delirious mad kick of surprise. You'll occasionally laugh out loud, but the heart of the movie is safe enough to chuckle at. B-