The images are startling. For sale on the Internet are videos that have recorded hundreds of fights in Arlington, Texas. Some of the fights appear organized, and the participants willing. But many of them show surprised, randomly chosen victims.
What is not random is the fairly sophisticated marketing and distribution of the videos. Six teens have been arrested on felony charges in connection with the videotaped fights. They seem motivated more by financial gain than thrills. The underground fight video, "Agg Townz Fights 2," which was filmed mostly in Arlington, Texas, has been sold online.
While the Arlington videos and fights are largely motivated by money, explained Arlington Deputy Police Chief James Hawthorne, he said he is now beginning to hear from other communities around the country dealing with similar issues -- fights recorded on video and with cell phones, available on the internet.
The videos have hit a nerve in the local community, especially with school about to let out for the summer.
"Like most people, shocked, appalled, honestly, ashamed, embarrassed. They come from good homes, good backgrounds, but on the videos, their activities look to be barbaric" said Reverend Dwight McKissic of Cornerstone Baptist Church in Arlington.
Chief Hawthorne said being shown in the videos has appealed to kids, who get some notoriety at school, and when the tapes are shown at parties. But what is a new activity in Texas is already a runaway hit in Great Britain.
It's a craze that has terrified many in London. "Happy slapping, the practice of attacking random people by slapping or hitting them and then videotaping the event, has escalated in severity.
It can happen anywhere, anytime -- on the street, on the bus, in the classroom
One teenager -- it is usually a teenager -- attacks an unwitting passerby while another films the assault on a cell phone.
The clip then spreads like wildfire, presented as an amusing blooper sent from phone to phone, posted on the Internet or e-mailed.
Some of the assaults "Nightline" saw were real, some fake.
Just a bit of childish, harmless fun, right?
"This isn't happy. It's not funny. Would you like your mother to see you in that position?" said Siobhan Christmas, whose son, Triston, was attacked in February."Would you? It's nothing more than glorified bullying."
"Nightline" met Siobhan Christmas at a cemetery just outside London, at the grave of her 18-year-old son, Triston. He was killed by a so-called happy slapper. On a night out last year, Triston was punched so hard that he reeled backward, smashing his head on a concrete floor. He died a week later. Siobhan saw cell phone images of her son, blood oozing from his mouth and ear as he tried to speak.
"Did it make it worse for [me] as a mother?" Christmas asked. "Yes, much worse. It's the images. I'd have rather he, and this is going to sound completely sick in the head, if he'd been hit by a car, it would have been better."
As Triston lay writhing on the ground, his killer and the killer's gang went to a party and blithely sent the images of Triston to friends.
"The fact that he put it out to everybody to say, 'I'm really cool,'" Christmas said. "Look what I done to Triston Christmas. That's more hurtful."
Police investigating the murder seized cell phones from teenagers at the scene and found 14 other "happy slapping" incidents. The victims were found, and the perpetrators prosecuted.
"Unfortunately, it is all too common and I don't like the term 'happy slapping,'" said Detective Chief Inspector Ellie O'Connor. "I think it undermines what is essentially a serious assault for an unprovoked reason. In my view these are serious attacks. There doesn't appear to be any motive whatsoever, and it seems to be innocent members of the public that are being affected by it."
Why is this sweeping Britain? And why now? The advance of cell phone technology is a major factor, of course. Britain and Europe have embraced that technology.
Many think the craze was inspired by TV shows like "Jackass," which glorify public humiliation and pain. Happy slapping began on London's subway trains and quickly spread to the schoolyard. John Carr monitors new technology and how it can harm kids.
"Bullying is as old as the hills," said Carr, Internet consultant and associate director of London's National Children's Home. "It's been around. I was bullied at school when I was a kid in the '50s and early '60s. But with mobile phones, what you've got is a new tool."
And millions of teenagers have that new tool. Ninety-seven percent of British 12-to-16-year-olds have cell phones. Most of those cell phones have cameras built into them. And they're easy to use. What I have just filmed I will now send to a friend's e-mail address. Minutes later, he can replay the clip and e-mail it on to all of his friends.
"Being hit in public, which is what historically bullying has been about, is bad enough and humiliating enough," Carr said. "But in general it was limited to just the small number of people who would be standing around at the time it happened.
Now the humiliation is compounded. Millions might see you degraded.
"Without any question for some children, what's far, far worse is the way that their humiliation is being multiplied and advertised and broadcast to people they know and people they don't know," Carr said.
Happy slapping has driven kids to suicide. Now British police are trying to convince kids this isn't harmless fun. And pop singer Myleene Klass, herself a happy-slap victim, is touring schools pushing the message. Some teens seem to be listening.
"They're serious, arrestable offences, and we will do all to bring these people before the courts," said school officer Paul Peterson.
Four teenagers were jailed recently after they attacked eight people in an hour-long happy slapping spree late one night on the banks of the Thames. One victim, a 37-year-old barman, was killed. A 14-year-old girl who filmed the attacks and kicked the barman in the head was convicted of manslaughter.
"Maybe if we had known earlier how this technology was going to develop here in Britain we would have been out of the traps a bit quicker with public education and awareness programs," Carr said.