Lil Uzi Vert performs at the Anthem in Washington. (Kyle Gustafson for The Washington Post) )

At a rap concert, the DJ sets the tone and hypes the crowd. Maybe he’ll scream, “You got a hundred-dollar bill, get your hands up!” like Fatman Scoop. But when the DJ says, “If you have straight A’s, make some noise!” you know you’re in for an entirely different experience. That was the case Friday night at the Anthem, which hosted its first hip-hop concert, headlined by Philadelphia rapper Lil Uzi Vert.

Don’t judge one of rap’s most exciting new personalities by his cover: The 23-year-old’s facial piercings and mop of magenta dreadlocks belie the soft edges of his music, which bakes heart-on-sleeve honesty and playful sing-rapping into songs built on top of trap beats and video-game sound effects. And while he names Marilyn Manson as his chief influence, he owes more to third-wave emo, with his petulant pop-punk melodies and lyrics about young love damaged by jealousy and infidelity.

Those lyrics certainly resonated with his audience, a group that was mostly underage (judging by the short lines at the bar) and underdressed (considering the freezing temperatures outside). Imagine 6,000 teens turning a warehouse into a parentless playground, throwing coats overhead like deflated beach balls to pass the time until Uzi took the stage.

Lil Uzi Vert performs at the Anthem in Washington. (Kyle Gustafson for The Washington Post) )

Once he did, it was a nonstop audiovisual onslaught. At this type of concert, disorientation is de rigueur, with more bass than the human body knows what to do with, a light show as blinding as the music is deafening, and quick-cutting videos and 3-D graphics: a goth apocalypse of skeletons, hellfire and anime that can keep even the most attention-deficient audience rapt.

Against that backdrop and in front of three inverted crucifixes (perhaps a nod to his Manson fandom), Uzi bounced across the stage, less a musical performer and more an avatar. He lived up to his self-described “rock star” persona with coquettish shoulder rolls and Jaggeresque prancing, and the fact that he can’t hit many of his notes or lyrics doesn’t matter. He wasn’t there to re-create the record. He was there to re-create emotions.

Philadelphia rapper Lil Uzi Vert’s songs have a soft, heart-on-the sleeve quality. (Kyle Gustafson for The Washington Post) )

Uzi was at his best spilling his neon guts on songs that revisit the heartache and anger of his breakup with his longtime girlfriend. His lyrics and melodies sounded more like Brand New than Brand Nubian, as he sang along with an electropop sample on “The Way Life Goes” or wailed the chorus on his hit “XO Tour Llif3,” a song with a couplet — “Push me to the edge / all my friends are dead” — that just might be the apex of emo.

But like his fellow rock-star rappers, Uzi hasn’t mastered the dynamics of a concert. He had the DJ play “XO Tour Llif3” a second time, asking, “Who knows the whole song?” before arcing the microphone into the crowd. Sadly, no one was brave enough to pick it up and have their own emo-ment. After that, he performed a few more songs, but after the catharsis of “XO,” it was impossible to recapture the magic. Oh well: Like his audience, Lil Uzi Vert has some growing up to do.