A lyric in a song known as "Dre Day". This was a song created in 1992 by Dr. Dre, Snoop Dogg, and featured a few other rappers. The lyric: "So if you want to keep poppin that shit and get your mother fuckin cranium cracked, step right up!"
This is probably what a lot of people on this site are probably going to end up have happening to them.