The video that made Earl Sweatshirt a star lasts only two and a half minutes, and when it appeared on the video-sharing site Vimeo, on May 26, 2010, most viewers probably didn’t know what to make of Earl Sweatshirt, or why he was in a hair salon, beneath a dryer hood, especially since his head was shaved nearly bald. He was sixteen then, with an oblong face, camel-brown skin, and wide lips. In the video, he seems to be shorter than most of his friends, who join him on a psychedelic adventure that is certainly—though not obviously—staged. A prescription-pill bottle is emptied into a blender, along with cough syrup, malt liquor, and something that looks like marijuana; the result is a nauseous gray-brown slurry that swiftly proves its efficacy. After choking down as much as they can, Earl and his friends grab their skateboards and head out into Los Angeles. They hallucinate, tumble off their boards, fight, convulse, and bleed. Earl spits out two teeth and pulls out a fingernail; by the end, nearly everyone is catatonic, or foaming at the mouth, or both.

This was, by the way, a rap video, and it’s no small tribute to Earl Sweatshirt to say that his rapping was not in the least upstaged by the images that accompanied it. His voice has a pubescent twang, but he sounds disconcertingly calm and clear, especially given his chosen subject matter. The song, which is called “Earl,” turns scenes of horror-movie hedonism into tongue-twisting provocations:

Go on, suck it up—but hurry, I got nuts to bust and butts to fuck and ups to chuck and sluts to fuckin’ uppercut. It’s O.F., buttercup. Go ahead: fuck with us.

O.F. stands for Odd Future, the hip-hop crew that comprises most of the young people in the music video. (The full name is Odd Future Wolf Gang Kill Them All Don’t Give a Fuck Loiter Squad—although that’s just one of many full names.) The “Earl” video, which has now been viewed more than three million times, led neophytes into the sprawling but insular world of Odd Future. There were eleven members, and dozens more affiliated skateboarders and scenesters; the group had a homemade Web page where fans could download their homemade albums for free, as well as a photography blog, Golf Wang (it’s a spoonerism), and a constellation of Twitter accounts. Their noxious attitude was seductive, and so, too, was their earnest devotion to the old-fashioned craft of hip-hop: subtle rhythms and unexpected rhyme endings, do-it-yourself beatmaking and engrossing storytelling.

In the year since the release of the “Earl” video, Odd Future has made a steady but extraordinarily steep ascent, which has been marked by a series of surreal milestones: the time Snoop Dogg registered his approval, on Twitter; the cover story in Billboard, with a headline saying that the group “may just be the future of the music business”; the performance on “Late Night with Jimmy Fallon,” which ended with one of the members jumping on Fallon’s back. Odd Future is the first major hip-hop movement that is primarily an online phenomenon, and, in that sense, the group’s sudden rise can seem not only inevitable, in retrospect, but overdue. The members became viral stars long before they were proven ticket-sellers, let alone record-sellers; they built their audience almost entirely through streams and downloads.

As Odd Future has barged into the hip-hop mainstream, it has charmed listeners by sneering at them. A recent article in the Guardian called Odd Future “the world’s most notorious rap group,” which is indisputable, although it should be noted that this title has been vacant for some time—in hip-hop, notoriety hasn’t been in fashion since the early days of Eminem. Odd Future’s willfully repugnant lyrics—the verses contain plenty of violent sexual fantasies, and “faggot” is frequently deployed as a term of address—are designed to nettle cosmopolitan listeners who have come to think of themselves as generally unnettlable, adding an unmistakable element of cruelty to music that can otherwise seem playful. There is something profoundly nostalgic about this strategy: Odd Future sometimes seems intent on resurrecting the bad old days, when hip-hop was scary, even if that means concocting sadistic fantasies or reinforcing old prejudices.

The Odd Future charge has been led by the group’s founder and mastermind, Tyler Okonma, known as Tyler, the Creator. He is a twenty-year-old auteur, rapper, designer, and musician (he created the murky but propulsive beat for “Earl”), who might be described as “lively”—but only by someone prone to understatement. The rise of Odd Future has turned Tyler into a new-media celebrity, a role he was born to play. After a recent performance at the Coachella festival, he wandered into the festival grounds and wasn’t entirely unhappy when well-wishers noticed him and gave chase. On his @fucktyler Twitter account he wrote, “OMG Fucking Just Ran From A Pack Of Fans Threw Coachella. Shit Was Wild!”

The other members of the group have become cult celebrities, too. Hodgy Beats, a diminutive, quick-tempered rapper, is the group’s hip-hop traditionalist and also its self-proclaimed “vice-president”; he is half of the duo MellowHype, along with an eccentric and laconic producer who calls himself Left Brain. Two more rappers, Domo Genesis and Mike G, are known for unhurried verses that both proclaim and evoke their shared dedication to marijuana. Matt Martians makes spaced-out funk. Travis Bennett, known as Taco, and Jasper Dolphin are members but not really musicians; their uselessness has become a running joke. Taco’s sister, Syd (the Kyd) Bennett, is the group’s d.j. and recording engineer. And Christopher (Lonny) Breaux, known as Frank Ocean, is in many ways an anomaly: both the newest member (he was inducted last year) and the oldest (he is twenty-four), he is also the group’s lone singer and the only member with a major record deal—he signed with Def Jam Recordings before he joined Odd Future.

For the past year, though—since shortly after the release of the “Earl” video—Earl Sweatshirt himself has been missing. He hasn’t been making public appearances with the group, and it seems he hasn’t been making private appearances, either. Last summer, a gnomic message appeared on the group’s Tumblr page: “Free Earl.” In July, when the group announced its first proper home-town concert, at the Key Club, in West Hollywood, the official flyer had Earl’s name crossed out and a terse explanation: “Will not be there due to mom.” Earl was still absent in October, when the group played a show in London, at the invitation of the British independent label XL, and, later that month, in New York, where teen-age fans and music-industry executives crowded into a basement and rapped along. But by then Odd Future had turned “Free Earl” into a rallying cry, and it was chanted long and often during the New York show. Because the members declined to say where or what, precisely, Earl needed to be freed from, many fans assumed his mother was the culprit. He was some sort of hip-hop prodigy—the most exciting rapper to emerge in years, a virtuoso who was just starting to figure out what he could do with words—but he was gone. One day last December, Tyler sent out a Twitter message that was at once uninformative and, in its way, deeply affectionate: “DAMN, EARL AIN’T HERE. LETS SWAG IT OUT FOR THAT UGLY ASS NIGGA.”