There's a new, dangerous game gaining popularity with New Jersey teenagers called 'Knockout.'

A man is about to be punched as part of teens play "Knock out" (YouTube)

Participants play the game by sneaking up behind an unsuspecting stranger on the street, and punching them as hard as they can, trying to knock them unconscious.

So far, several victims have been seriously injured, and a few people have even died.

"This is horrible on many levels. I think it speaks to how kids nowadays are completely desensitized to violence, it's just part of their life," said child psychologist Dr. Steven Tobias.

He said it's very concerning that kids view violence as entertainment.

"That's what all these video games are about," Tobias pointed out. "It's fun to shoot people - it's a horrible message for kids to be getting."

Dr. Tobias added there's a lot of violence that's part of our general culture, and there's not as much parental involvement as there used to be - kids used to still have dinner with their parents, they touched base with their parents, and that helped them stay out of trouble.

Rutgers sociology professor Dr. Deborah Carr stressed it's important to remember that only a small minority of teens are pushed "over the edge" and participate in such behavior.

"It does speak to the recklessness of teens, and their ability to dehumanize people whom they do not know," Carr said.

She pointed out sometimes, young people do not or cannot think about the long term implications of what they're doing, and often times they don't estimate realistically how dire the consequences can be.

Dr. Carr added with video games and movies becoming increasingly violent, it desensitizes young people.

"They see all the time in a video game that you can kill someone and then continue to have fun playing the game," she said.

Acting Attorney General John Hoffman said it's a terrible and repulsive assault issue, with some sort of premeditation,

"It's certainly one that it's a game that people are playing - it's certainly not a game at all, it's completely repugnant," Hoffman said. "We're aware of it, we have no reason to believe it's particularly widespread, but to the degree to which people are doing it, engaging in it, we're going to prosecute them to the fullest extent of the law. It's unbelievably reprehensible."