Earl Sweatshirt performs at the 9:30 Club. (Josh Sisk/For The Washington Post)

Midway through his concert Monday night, Los Angeles rapper Earl Sweatshirt asked the crowd, “Are you guys proud of yourselves?” Like most of his interactions with the audience, the sentiment was somewhere between sincere and sarcastic, but the kids standing in the sold-out 9:30 Club didn’t care: Getting teased by Earl Sweatshirt makes you part of his crew.

Still a week shy of 20, the Odd Future rapper already has the devoted following and outsize legend that most artists twice his age can only dream of. Two years “free” of a Samoan therapeutic retreat (his unknown whereabouts inspired endless sleuthing and theorizing on the Internet) and six months after the release of his debut album “Doris,” Earl is quickly and definitively delivering on the promise of his early work.

In the same way that he dazzled with “Doris,” Earl performed with a presence and skill that belies his age, never getting lost in the tangle of syllables in his densely written songs. Joined by frequent collaborator Vince Staples and DJ/court jester Taco Bennett, Earl treated the gig more like an episode of Odd Future’s Adult Swim TV sketch show “Loiter Squad” than a pure concert. Between songs, the three would lounge at the DJ table, catch their breath and banter among themselves and with the crowd, busting chops as adolescent guys tend to do.

The contradictions that make him such a compelling artist — on “Doris,” Earl is supremely confident one moment and self-loathing the next — affect the live show, too. He told the crowd he wouldn’t play one of his most reprehensible songs, the rape-and-murder fantasy “epaR,” yet he had no problem playing “Earl,” a song awash in the kind of violent misogyny and homophobia that Odd Future is known for.

No matter how vulgar and violent the lyrics, Earl’s self-awareness makes them easier to accept: The impish goofball on stage cannot possibly be as depraved as his songs suggest. That quality was on display Monday night, whether he was deconstructing the absurdity of some of his most vile lyrics — displaying mock horror at their literal meanings — or asking the 9:30 Club technicians for a “dark and ominous light” before performing the confessional “Chum.”

The crowd, made up mostly of his peers (plus a handful of dutiful parents), was entranced throughout, rapping along and chanting at all the right places. The front half of the room lurched like an amoeba with the testosterone-fueled mosh pits and crowd surfing more common at punk shows. Earl certainly feeds off the crowd’s energy. Encoring with “Drop,” he boasted, “show me a rapper my age that say he nice as this,” and judging by the crowd’s reaction, you’d be hard-pressed to find one.

Kelly is a freelance writer.