strong bad's special power is popping the cap off of a cold one, or homestar's head.
To shoot someone, most likely a hater of some sort. Usually a gansta, will make this threat. But on occasion a wanksta, will make this threat you can usually tell the two, for example a gansta will be an angry black man screaming and making a big deal about something very small, and a wanksta will be the white guy in baggy pants of some sort and wearing a 5XL shirt trying to look hard but making a fool of himself.
"Fool you best back up befo' I pop a cap all up in yo' head."
a line often heard in gangsta rap meaning to pop a cap in a cop. because blacks are fucked over by cops all the time and they have had enough of that bull shit.
whats your take on that line John pop a cap in the devil.