A YouTube video has gone viral that shows a black teen slapping a black Wendy's cashier in the face and then running away -- part of a little-known trend called "smack cam." The incident provides an unsettling glimpse into black-on-black violence -- and black thug culture.

The incident in Austin, Texas, is being investigated by the local police. It is especially disturbing because of who was involved: not only two black teens or pre-teens but a black adult female who appears to be a guardian or role model. Identified as "CB," she drives the get-away car; it's not clear if she also narrates the video. Referring to the hapless cashier as the video starts, she or an unseen narrator cheerfully explains that they are "gonna do the smack cam on this nig*ah." Next, a young teen identified as "Lil Rick" shyly approaches the counter  -- then suddenly slaps the unsuspecting cashier, 16-year-old Calaybra Jones. Another teen records the incident with his smart phone.

Their video briefly popped up on the YouTube site of Austin rapper Kade Fresco. But after news reports of the incident stirred public outrage, the video disappeared -- only to be quickly reposted by an outraged resident.

 “I'm sad. I'm angry," Jones told a local news outlet. "It’s just shocking that they would do that to someone that they don't even know.”

 Police have identified the suspects and expect to make arrests in what is the first case of "smack cam" in Austin to draw wide attention. The game, however, is a little-known national trend that has been around for a while and that involves mostly black participants. In recent months, however, it has been overshadowed by the more violent knockout game that involves black-on-white violence. The goal there is to knock out a random white victim with a sucker punch.

The Wendy's assault, to be sure, is hardly the first case of black thug violence in Austin -- a hip college town, hi-tech Mecca, and the state's capital.

Last October, Austin residents were stunned when hundreds of rampaging black youths converged by a shopping mall one evening. They walked atop parked cars, fought among themselves, and hurled rocks at scores of police officers arriving from other parts of the city. Police called it a full-blown riot but never figured out what set it off.

And at Austin's recent South By Southwest music and film festival, a 21-year-old black rapper named Rashad Owens plowed his car through barricades and raced down a crowd -- killing four festival goers and injuring 20. Owens, whose rap sheet included criminal mischief and drunken driving arrests, had been eluding a police officer attempting to stop him for an illegal turn and driving with his headlights off.

And in another incident at the festival, a 23-year old rapper named Tyler Gregory Okonma ( "Tyler, the Creator") was charged with inciting a riot. He had exhorted his fans to push past security at a downtown club.  

Austin, a politically liberal Mecca in a red state, is governed by guilt-ridden liberal Democrats. They are proud of Austin's diversity; the fact that it's no longer a "whitopia" -- as it was during the bad old days of Jim Crow, and before they turned it into a sanctuary city whose white population is slipping toward minority status. Segregation and racial injustice are long gone: good riddance. Unfortunately, the apparent emergence of a black thug culture may be a harbinger of things to come.