CRKFO is an abbreviation for the "Carrick Fair One".
This saying
originated in Pittsburgh, PA. It refers to the way that citizens of the Carrick community/
neighborhood fight. The Carrick Fair One is actually saracastic, because people from Carrick do not, in fact, fight fair. CRKFO usually refers to multiple people from Carrick fighting (or jumping) one foreigner (or other Carrickter).
CRKFOs are known to get
out of control, and often be comical as well.