It took the sibling rappers in Rae Sremmurd precisely one song for T-shirts to come off and become hype props Friday at the Blue Stage. It was during 2014’s "No Flex Zone," one of the most unhinged, Earth-shaking singles in recent rap.

The understated, nuanced poetry of "No Flex Zone" elicited an army of sugar-rush fans to dance in place while bending their elbows up at their shoulders as if they were holding barbells: "Freak hoes, got several. They tens or better. I’m a trendsetter. I’m a go-getter!" Two songs later, the stage-diving commenced.

Atlanta’s Rae Sremmurd is, for the uninitiated, brothers Khalif "Swae Lee" Brown, 19, and Aaquil "Slim Jimmy" Brown, 21. Thin, diminutive, and sporting short dreads, the duo brings back memories of precocious ’90s party kids Kriss Kross. But the comparison stops at physical features and buoyant energy. These dudes are bold auteurs with jubilant, distinct voices–this double-timed, bird squawk-like vocal jabbing that Ping-Pongs back and forth as the brothers flip between singing, rapping, and yelling standalone nouns.

Rae Sremmurd is "Ear Drummers" backward, which is their label’s moniker, and in little more than a year the band commands a passionate fanbase built off all-star producer Mike Will Made It’s doom-laden trap beats. At one point in the show, noticing a particularly turned up fan, the duo just handed him a microphone and asked the kid to speak: "Sremmlife or die!" he yelled as if on cue.

That’d be the title of January’s debut album, one that features blockbuster songs like the Nicki Minaj-featuring "Throw Some Mo," and maybe the most poignant track of the times, "Up Like Trump." The song is slang-driven and not political, but "Up Like Trump" was introduced with a quick plea to vote (tragically the plea came just days after the $287-million courthouse bond was voted down); then a nice "f**k that n***a" chant hurled at the Donald himself.

Other highlights included an inspired rundown of their part from Ty Dolla $ign and Future’s "Blasé," and bringing out Ear Drummer labelmates, and early afternoon Blue Stagers, Two-9. That undercard hip-hop group rolls five large, and coupled with the perpetual rap concert trope of bringing a cluster of young ladies on stage to dance, made for a fairly incoherent and bloated final third to the set. But, to be fair, it was definitely a turnt up experience for the faithful.