Tell somebody from the year 2003 that the producer half of Lex Records cult-rap act DM & Jemini would team up with the recently solo Goodie Mob alumni CeeLo for one of the decade’s most definitive singles, and they’d think you were out of your mind. Tell somebody from the year 2006 that the song feels like a lucky yet brief radar blip in the midst of two wildly diverging musical careers, and they’d probably have the same reaction. But few acts of the aughts have that similar “where’d they come from”/”where’d they go” push-pull as Gnarls Barkley, whose “Crazy” made a one-hit wonder out of two artists you could hardly call that when separated. The song, which was officially released on 3/13/06, may have been ubiquitous to the point of instant familiarity — hands up, who got it stuck in their heads partway through this first paragraph? — but the more angles you look at “Crazy” from, the weirder it gets that it’s had this much of an impact on pop music. Here it is from a few different points of view.

The Lead-Up

As 2002 came to a close, producer Danger Mouse and singer/MC CeeLo Green were in two different but increasingly adjacent spaces in hip-hop. DM had just teamed up with longtime signed-and-dropped industry casualty Jemini The Gifted One, and dropped a 12″ of “Take Care Of Business” which featured legendary shit-talker deluxe J-Zone and a beat that sounded like a kaleidoscopic dream-pop mutation of Slick Rick’s “Mona Lisa.” (An early sign of DM’s unconventional ear, he sourced that vibe from “Poem Of Dead Song,” a 2000 deep cut from indie-psych greats Broadcast.) CeeLo, meanwhile, had just put out the modestly successful Cee-Lo Green And His Perfect Imperfections, his first solo record after splitting with crucial Atlanta rap icons Goodie Mob in the wake of World Party’s scattershot pop moves. Perfect Imperfections was ambitiously built to showcase CeeLo as a genre-defying eclecticist who could mess with R&B, gospel, rap, funk, psych, jazz, and even country; naturally the album closes with a skit where he’s asked “Well damn, Lo, what don’t you do?” His response: “Bullshit! Hooo!“

2004 is where things really picked up: In the midst of the early-’00s mashup craze, Danger Mouse’s Beatles/Jay-Z fusion The Grey Album was a stunt-casting novelty that became famous off its premise and aged well off its execution (of course “99 Problems” rips over beats sourced from “Helter Skelter”). Cee-Lo Green … Is the Soul Machine further solidified CeeLo’s rep as a do-anything sort of artist; not simply content to coast off the genre-hopper smash success of fellow Dungeon Family member Andre 3000’s The Love Below, he made a point of streamlining his stylistic restlessness into a more classic hip-hop package that still let his weird side shine. (This time around, the answer to “what don’t you do” was “Fuck around!”) If the Gnarls Barkley partnership seems to make more sense in hindsight, it didn’t seem all that weird just going off what those two pivotal artists had done up to that point.

The Origin

The specifics of how Danger Mouse and CeeLo first met are a little vague, in keeping with the air of mystery they wanted to maintain around the Gnarls Barkley project. But the backstage talent-show introductions that first got the still-Goodie Mob member and the still-obscure DJ to float some collaboration ideas first sprung up on a DM & Jemini release, 2003’s Twenty Six Inch EP. Big-butt anthem “What U Sittin On?” was remixed with a searing sing-rap CeeLo hook and a neon-glow music video that split the difference between Ralph Bakshi and the nascent Adult Swim aesthetic. CeeLo was impressed enough by the various slates of beats that DM played for him later that future collaborations were planned, even though (according to a 2006 Pitchfork interview) Danger Mouse claimed “I don’t really do tracks … I do albums.” They continued to work together, though, with CeeLo making another appearance on a Danger Mouse-produced track when he showed up on Danger Doom’s The Mouse And The Mask to guest on “Benzie Box.”

But while further demos were cut and ideas for an album weren’t far from their minds, the combined breakthroughs of The Grey Album, Soul Machine, and DM’s work on Gorillaz’ album Demon Days meant their partnership wouldn’t become a widely known quantity until “Crazy” broke through. And even then, it took a while for listeners — and the industry — to really get a grip on just who they were. In the meantime, their deal with Downtown Records — chosen for their indie-with-major-resources backing — offered them creative freedom, which was only bolstered when “Crazy” leaked in late ’05 and immediately got spins from tastemaker DJs like Pete Tong and Zane Lowe on the UK’s Radio One.

The Voice

I’ll leave it to the argument-starter set as to whether this is CeeLo’s greatest vocal performance — he’s got far too many candidates from Soul Food onwards — but it’s probably his most famous one, or second to “Fuck You” at the very least. Even then, “Crazy” does even more than “Fuck You” to really get at what makes CeeLo such a grippingly weird artist. A versatile, rangy belter who just happens to sound like a superbike engine at full rev, CeeLo’s self-made image as an outsider with insider talent goes through all kinds of gymnastics around his lyrics — a theme inspired by a conversation the two had about the reputations of great artists being prone to insanity — and there are too many great touches to count. Some of the best: that immediate attention-grabbing opening repetition of “I remember,” the way his line “ha ha ha!/bless your soul” feints at sounding conversational before soaring at that last word, his wordless outro — and, of course, that chorus, where he sounds like Ann Peebles and Al Green at the same time. It took all of one take.

The Beat

While Danger Mouse has made a rep that’s as strong on traditional songwriting as it is on iconoclastic sample-flipping, he’s usually at his best when he can find an unusual source and zoom right in on it. One of his earliest ambitions was to make film scores, so it’s natural that he’d gravitate towards the kind of spaghetti Western scores popularized by Ennio Morricone — though “Crazy” digs a bit deeper past the Dollars Trilogy for something with all the resonance and little of the familiarity. The thematic refrain in Gianfranco & Gian Piero Reverberi’s 1968 score for Preparati la bara! (Django, Prepare A Coffin) — particularly the piercing strings and sparse bass guitar-and-choir parts of “Nel Cimitero di Tucson” (“Last Man Standing”) — provides enough of the instrumental melody to earn them a songwriting credit, while the opening break to Garnett Mimms’ 1972 single “Stop And Check Yourself” (previously sampled by Blackalicious, DJ Premier, and Handsome Boy Modeling School) are ramped up in tempo just enough to make for an intense drum loop.

The Video

Downtown Records uploaded the official video for “Crazy” to YouTube on the first week of January, 2007. Since then, it’s been viewed nearly 76 million times, which makes it as strong a candidate for any as an example of how the music video tide turned from MTV to streaming. “MTV doesn’t play videos anymore” had been a gripe for at least 10 years previous, though it was still a major player in breaking them all through the early ’00s TRL years. YouTube’s debut in February of 2005 was the first step in really shifting the music video balance from cable to the internet, and while “Crazy” was a prominent presence in 2006’s MTV Video Music Awards, its staggering success as an online video helped point the way towards maybe the go-to method for listening to music.

The funny thing is that the video itself isn’t necessarily the defining aspect of the song’s streaming success. Art director Bryan Louie’s Rorschach inkblot animations were iconic enough to get nominated for three VMAs in ’06 (winning Best Direction and Best Editing but losing Best Group Video to The All-American Rejects’ “Move Along” for a category that was eliminated after 2007). And while the “Crazy” video is well-known to an extent, the absolutely brilliant clip for later single “Smiley Faces” where they play Zelig with the history of pop music has less than a tenth of the plays. It’s not necessarily streamed watching, but streamed listening that drew so many people to “Crazy” on YouTube, and the fact that it peaked at #1 on Billboard’s recently created Hot Digital Songs chart while stalling at #2 on the traditional Hot 100 chart for seven weeks is telling enough. Who knows how it would’ve done if Billboard had enacted their Streaming Songs chart and incorporated it into their chart positions by then — especially since its nine-week reign at the top in the UK was off the back of it becoming the first download-only #1 single in the country’s history.

The Impact

Everybody covered “Crazy.” Everybody. Some made sense on paper: the Violent Femmes repaid Gnarls Barkley’s “Gone Daddy Gone” cover with their own rickety version. Some seemed like cruel jokes played on the group by the fates: Nelly Furtado, who’d kept “Crazy” out of the #1 slot, included a twee “Radio 1 Live Lounge Session” cover of the song on the European CD version of the single, “Promiscuous,” that stifled it on the charts. Some versions — by sensitive folkie Ray Lamontagne, by punx-for-Christ Relient K, in a thankfully underdocumented impromptu performance by Billy Idol — felt intent on draining all the idiosyncracy from the song’s origins and performance and turning it into just another standard. Bettye Lavette came closest to making it her own; that anybody else bothered afterwards is kind of bewildering. But I guess once The Smooth Jazz All Stars Gnarls Barkley Cool Jazz Tribute broke open the floodgates, there wasn’t much anyone could really do to shut them.

And if that says anything, it’s a testament to the off-kilter crossover of “Crazy.” A product of two artists who had deeper ties to hip-hop than most artists to flirt with #1 chart status, Gnarls Barkley largely succeeded off something else — a rare willingness for the Modern Rock format to pick up a song that didn’t traditionally scan as “rock” in the post-AOR sense. Of course, it didn’t really traditionally scan as hip-hop circa 2006, either — at least not by an industry that still leaned on artists like 50 Cent and The Game — and it barely made a dent in the Hot 100 R&B/Hip-Hop Tracks chart. So all the arguments that started near the end of the decade about “hipster rap” and “PBR&B,” of music that broke with tradition to reach audiences outside who might not just be ignorant of but hostile to the original core styles, can be aimed at least somewhat towards Gnarls Barkley.

The Followup

St. Elsewhere was a generally well-received album, though later singles “Smiley Faces” and “Gone Daddy Gone” didn’t stick around quite as long. The Odd Couple hit stores less than two years later — pushed forward, like its predecessor, thanks to an internet leak — and felt like the kind of uncompromised-compromise situation that left them free to ruminate on what the success of “Crazy” meant, and to adjust accordingly. This meant that while “Crazy” only hinted at classic ’60s pop-soul through a contemporaneous alternate-reality lens where Holland-Dozier-Holland were way into the old Django movies, their further efforts wound up confronting a more direct classicism head-on, even if they weirded it up enough to succeed on their own terms.

There’s still no third Gnarls Barkley album, despite scattered promises that placed it somewhere in the vicinity of a 2013 that’s long in the rearview. CeeLo went on to “Fuck You” and The Voice and a pop-cultural status that’s shifted even further away from his status as the brilliant does-it-all artist that came up through the Dungeon. Danger Mouse went from master-of-bricolage beatmaker to a jack-of-all-trades producer who played down his wilder eccentricities to give shine to Beck and U2 and Norah Jones, though he at least had the leeway to follow up his Morricone enthusiasms with composer Daniele Luppi on 2011’s long-gestating Rome. So maybe those two careers — two careers irreversibly altered by the success of one massive hit — have made it hard to imagine a Gnarls Barkley reunion that would feel even remotely similar as the conditions that first produced them. But crazier things have happened.