Mustard will run 2015 just like he did 2014. But the next sound coming on his tail isn't popping out of Atlanta, it's popping out of Chicago. The Bop production style—particularly the beats of producer Mudd Gang—is a fresh, uptempo sound easily adaptable to R&B and hip-hop. It sounds like nothing else on earth—just listen to “Fiesta” or (especially) “Jockin” (above)—yet could easily be adapted to rhythmic radio. If it happens, it will be a slow rise—but you just need one “Rack City” domino to set things off.