These days a portion of the music-consuming public talks about CDs as if they’re the child kept in a crawl space beneath the stairs and fed an unsteady diet of fish heads. When it comes to music media, even the eight-track tape has more cool cachet. But CDs still move, albeit in fewer quantities than in decades past: Nielsen Music reported that in 2014, U.S. retailers sold 140.8 million. As long as artists still put out music on CD, it’s hard to truly abandon the format, and many music shops still have a dedicated CD section. The one at Laurie’s Planet of Sound is small, but the collection devoted to Chicago MC Sharkula is impressive—larger than the rest of the hip-hop discs on hand. Shark, aka Thigahmahjiggee—or Dirty Gilligan or Brian Wharton, his birth name—has been peddling his music on the city’s streets for a couple decades, and his primary format for a long portion of his career has been the CD-R. If you want to become a Sharkula completist or dip your toe in the deep water of his catalog, start here.