What’s wrong with this picture: Being John Malkovich. Adaptation. Where the Wild Things Are. Jackass Presents: Bad Grandpa? “One of these things is not like the others,” as they say on “Sesame Street.” “One of these things doesn’t belong.”

The first three are highly regarded Spike Jonze films. The one that doesn’t appear to belong is Bad Grandpa, but the amazing thing is that it is like the others. Jonze is one of its five writers.

I learned only recently that the visionary auteur and frequent Charlie Kaufman collaborator has been part of the “Jackass” scene since the beginning. The oversight might have something to do with my never having tuned in during the show’s three-season MTV run or watched even one of the three previous movies it spawned.

Those three debuted at No. 1 at the box office; 2010’s Jackass 3-D had the biggest fall opening ever. So sitting down for the fourth release in the shockingly profitable franchise, I had reason to believe there would be more to the phenomenon than its famously crude pranks and suicidal stunts. Imagine my surprise when I discovered there’s less.

One reason is that the gang’s not all here. Johnny Knoxville goes it alone in the latex guise of 86-year-old Irving Zisman, a character he introduced in the series’ last season. Another reason is that the daredevil antics are history. Bad Grandpa inaugurates a new generation of Jackass projects, a reboot necessitated by the reality that one cast member (Ryan Dunn) is dead and the rest are well into middle age.

For the first time, a Jackass production has a plot. It’s not much — sort of Borat meets ABC’s “What Would You Do?” with dick jokes — but it’s a plot. Irving’s wife has died, and he’s eager to make up for lost time with the ladies. Just as he’s about to blow his life savings on lap dances, though, his crackhead daughter is sent to the slammer, and he’s saddled with her 8-year-old son, Billy (Jackson Nicoll), who needs a cross-country ride to the home of his deadbeat dad.

The two climb into the old man’s Lincoln, and hidden-camera hilarity ensues. Among the high points: Irving attempts to rape a soda machine and — you guessed it — gets his prosthetic pee-pee caught in the coin slot as bystanders look on in bemused disbelief. He gets the same reaction when he publicly shares a six-pack with the boy, who promptly pukes his guts out. Ditto when the pair engage in a farting contest at a roadside eatery. Though the punchline is “Grandpa, you sharted!” and clearing their table will necessitate cleaning the wall behind it, never is heard a discouraging word from the onlookers.

As the closing credits show, the filmmakers were always nearby to reveal the joke. Consequently, the rowdy road trip never generates the sense that things might backfire with dire results, as did Sacha Baron Cohen’s Borat and Brüno. Those were gonzo high-wire acts by comparison.

As long, strange trips go, Irving and Billy’s feels more long than strange. It’s a timid, surprisingly saccharine 92 minutes by Jackass standards — and, given the participation of artists as creatively accomplished as Jonze, decidedly uninspired. Not that it matters, given the loyalty of the franchise’s base.

Once again a Jackass movie has debuted in the No. 1 spot. A comedy featuring maybe a half dozen solid laughs and no real outrageousness nonetheless brings in double its budget in three days and knocks down a film as great as Gravity after its three weeks there. These merry pranksters may no longer risk life and limb for their art, but Bad Grandpa leaves little doubt they can still shock. If only at the box office.