The Golmok Jo-pok[a] may not be an entity of organized crime, nor even a gang, but they are certainly a curiosity that is worth exploring.
In and of it self, 'Golmok Jo-pok' is a term coined by South Korean police and media which means 'Backstreet Mobster'.
But what is a Backstreet Mobster? At first glance, one might expect this to be the name applied to local street gangs similar perhaps in the way Japanese Yakuza are referred to as the Boryokudan[b]. Or, perhaps it is even meant as the name of a single street gang it self. On the contrary, the term Golmok Jo-pok is applied to singular individuals who engage in acts of blue collar crime without the backing of any sort of criminal syndicate to support them.
Typically, these individuals appear to be homeless in nature, or are at least low income earners. They prey upon small businesses and seem to frequent the same areas again and again, as if to treat the very same businesses they wreak such havoc on as their own personal playgrounds and hang outs.
(Disclaimer: This is not an attempt to criminalize homelessness. Homelessness is a serious and unfortunately growing issue, one which is often stigmatized wrongly by those of greater fortune and/or privilege. It is worth noting that the majority of homeless cases are not due to drug dependencies or other criminally deviant behaviour. Instead, they lay in economic issues such as unreasonably high rents, job losses, or are the result of mental health conditions that render the afflicted unable to work. The Golmok Jo-pok represent a minuscule percentage of homeless and low income individuals.)
The actions of these persons can sometimes be violent in nature, such as assaulting passersby, hurling insults or threatening people with weapons of a blunt or edged design. Most typically though, the Golmok Jo-pok seem to prefer verbal confrontation. The aforementioned verbal abuse and the muttering of threats is a preferred method of coercion.
But to what end? Well, given their often transient existences, the aim is typically to procure a free meal, a free drink, or to extort from passersby and business patrons alike a payment.
As in most cases of extortion, this can be just as much a solution as it is a cause for continuing issues. Once they've realized they can get something from you, they're apt to return to demand more until such time the victim wises up.
Source material & lexicon
[a] - A Korean term meaning 'Backstreet Mobster'. [b] - A Japanese term meaning 'Violent Groups'.