From left, Zach Holmes, Johnny Knoxville and Rachel Wolfson in “Jackass Forever.”

The opening sequence of “Jackass Forever” is one you’ll never forget. It’s a piece of filmmaking so bold, so audacious and so unbelievably, sublimely stupid that it will no doubt etch itself on your brain for years to come. I don’t dare describe it in print, because everyone deserves to discover it for themselves. Let’s just say it’s “Godzilla”-inspired, with a uniquely “Jackass” twist.

“Sublimely stupid” is what the “Jackass” crew does best, and their formula (thankfully) hasn’t wavered since the prank/stunt reality comedy show debuted on MTV in October 2000, and evolved into a film franchise spanning two decades. There’s something comforting about the phrase, “I’m Johnny Knoxville, welcome to Jackass,” even, no, especially, if what comes next is a display of pure human agony and humiliation.

Knoxville, our devilish ringleader, sports his signature Wayfarers and coif, which he allows to go silver at some point in the filming, which is a sort of sweet display of how long he and the crew have been up to these antics, and how long we’ve been watching them. He is a circus ringmaster, a rodeo clown and a sadistic game show host, but always, his most important role is the one of big brother. While he freely dispenses surprise Taser attacks, he’s always the first to offer a high-five, the one laughing the loudest. Though “Jackass Forever” puts the cast member’s soft tissues through a pummeling like never before, it’s not the violence that puts a smile on your face, but the riotous back-slapping that follows the screams of agony after each pratfall, prank and punch.

Knoxville and his original compatriots, Chris Pontius, Steve-O, Danger Ehren, Dave England, Preston Lacy and Jason “Wee-Man” Acuña, are joined by a new crew of masochistic pranksters, including YouTube stunt-ster Zach Holmes, comedian Rachel Wolfson, Eric Manaka (who appeared in Knoxville’s “Action Point”), Odd Future member Jasper (plus his father, Dark Shark) and pro surfer Sean “Poopies” McInerney, as well as guest stars such as Tyler, the Creator, Eric Andre and Machine Gun Kelly. The newbies seem astonished to be included in something they grew up watching, and that exhilaration and awe seems to power them through each bone-crunching, stomach-churning stunt.

The OGs pony up to the plate for their share of pain and humiliation too. Knoxville ends up fairly battered and broken, Steve-O subjects himself to stunts this shy of a cavity search and Danger Ehren takes the classic “cup test” to new levels. This film, directed as always by Jeff Tremaine, is very much focused on the members of the members of this crew, who subject their nether regions to astonishing injury. There’s never, ever been full frontal like this before, in fact, the word “frontal” isn’t even an apt descriptor for this display.

“Jackass Forever” transcends the body horror to achieve a kind of nirvana: The crew invites themselves to laugh so they don’t cry, and asks the audience to do the same. It’s a reminder that pain is temporary, but friendship is forever.

3 stars (out of 4)

MPAA rating: R for strong crude material and dangerous stunts, graphic nudity and language throughout.

Running time: 1:36

Where to watch: In theaters