Ever since ‘This Is Spinal Tap’ created the modern mockumentary form, comedy filmmakers have chased the dragon of that dumbbell music doc spoof. The subject matter is just too rich. Over-privileged morons ranting about their greatness between song parodies? That’s funny in the bank.

It’s pretty much impossible to match the ‘Spinal Tap’ magic, of course, but some folks come close. The take on that very specific genre that just shot onto screens from the Lonely Island gents (that’s Andy Samberg, Jorma Taccone and Akiva Schaffer for those keeping score) might be the best since Christopher Guest and the gang cranked things up to eleven. Playing off the brand of catchy pop music idiocy the trio perfected on ‘SNL’, as well as the recent overblown music profile docs about the likes of Justin Bieber and Katy Perry, ‘Popstar’ plays like a glossy blockbuster edition of ‘Spinal Tap’.

The movie is about Conner4Real (Samberg) a vapid, tattooed, stupidly wealthy, and just plain stupid pop star with a touch too much ego. His career began in the late ’90s with a rap trio featuring his childhood friends (Taccone and Schaffer, naturally), but through that magical mixture of success and ego anyone who pays attention to pop music knows too well, he left to go solo. His bandmate who wrote all the famous lyrics left to become a farmer in Colorado, while the one who made the beats stayed on to essentially operate an iPod as Conner’s DJ/hype man.

Conner’s first solo record was a hit, so the doc is supposed to be a chronicle of the follow-up album’s culture-crushing success. It doesn’t quite work out that way, though. There are some hiccups, like a plan to release the first singe through all refrigerators across the U.S. that obviously doesn’t go very well. Reviews are harsh, ticket sales are pitiful, and Conner heads into celebrity breakdown territory with his camera crew in tow.

For the first hour or so, ‘Popstar: Never Stop Never Stopping’ qualifies as one of the funniest Hollywood comedies to come around in a while. With all the Lonely Island boys in place both in front of and behind the camera, the movie captures their distinctly surreal and viral video tone. The songs are impossibly catchy despite being completely ridiculous, from an anti-discrimination anthem with Conner screaming that he’s not gay, to a track about a woman who mixes sex and Osama Bin Laden to curious effect. If you heard any of the songs the band whipped up on ‘SNL’ (and how could you not during those years?), you’ll know how good these guys were at capturing a proper Top 40 sound with ludicrous lyrics, and that hits home perfectly here. They’ve lost none of their comedy music chops.

The plot unfolds episodically and insanely, which is true to the form of these sorts of docs and works. There’s hilarity to be found in Conner’s ridiculous entourage, featuring members who are there purely to make him look taller or to punch him in the nuts to keep him humble. Samberg is delightfully innocent in his vapidity, while his Lonely Island mates play to their oddball strengths on the sidelines (as well as co-directing with style). Folks like Sarah Silverman (as Conner’s publicist), Tim Meadows (as his manager), Bill Hader (as his ‘Flatliners’-obsessed roadie), and Will Arnett (as a perfect ‘TMZ’ parody) fill out the cast to ensure no scene goes by without a big laugh, while an endless stream of actual pop singers, hip-hop artists and producers turn up in tongue-in-cheek talking head interviews to establish the fictional singer’s music world dominance.

Sure, the satirical topic is fish-in-a-barrel territory, but the tone is so absurdly cartoonish and the execution so gleefully profane that it’s too much fun to think too deeply about. At its peaks, ‘Popstar’ is likely the funniest thing The Lonely Island have ever done and a perfect big screen translation of their specific talents.

Unfortunately, the movie starts to unravel once it succumbs to the needs of mainstream comedy. The Lonely Island boys have always been joke-first comedians. While their jokes can be smart and creative, their work has never had much emotional weight or the screen time to try. Working with Judd Apatow as producer, ‘Popstar’ has a reuniting/redemption arc baked in that dominates the third act and pops the absurdist bubble ever so slightly. It’s kind of like what happened to Amy Schumer last year in ‘Trainwreck’, delivering a genuinely unique Hollywood comedy before slowly slipping into formula and feeling like any other studio product.

That’s particularly rough here given that the tone is so surreal and irreverent. It’s hard to add emotional weight to these cartoon characters. Still, even when ‘Popstar’ gets a little too conventional, Samberg, Schaffer and Taccone are never more than a few seconds away from a good gag. This might not be a perfect movie, but it’s hard to imagine that any Hollywood comedy will serve up as many laughs this summer.