This is a once-in-a-lifetime collaboration. On yesterday’s segment of MTV RapFix Live, Houston rapper Bun B, New York’s own A$AP Rocky and the newest act out of Chicago Vic Mensa appeared and threw down some bars with veteran DJ Red Alert holding down the beat.

Vic stepped up first to drop his verse before the chief of the A$AP Mob went off on the mic and even had Sway start off the set. Bun B stepped in to set the newbies straight by shouting out Red Alert and more. The three rappers continued to go back and forth with other artists jumping into the cypher.

Check out the full set here.