Nicknames are very popular in the world of street gangs, some examples including "Lil' Capone," "Ghost," "Bats" and many more. Nicknames have become so commonplace in gang culture, in fact, that police departments now commonly maintain robust databases of these nicknames in order to track wanted criminals.
Many gang members operate under nicknames to give themselves a persona or possibly to instill a sense of family in their crime organization by using pet names. When a gang member is wanted for a crime, police often have trouble tracking them down because their associates will only know them by their street name. This is why police departments utilize the nickname databases so regularly.
Nicknames in gang culture are nothing new, though. Nicknames were very popular in the organized crime families of the mafia, with some some noted examples being the "Dapper Don" for John Gotti, "Scarface" for Al Capone and "The Breeze" for Frank Calabrese.