It's frightening, it's deadly and it's gaining in popularity. The 'Knockout Game' has police in several states on their heels.
It involves people going up to strangers, punching them and running off.
"The video speaks for itself, but I don't remember it happening when it happened." U nsuspecting 50-year-old teacher-- James Addlespurger-- walks toward a group of boys.
Mobile users view video here: http://bit.ly/17mreFI
Then, seemingly out of nowhere, one of the boys violently knocks him to the ground. H is limp body lies on the concrete as the group walks away.
"I was shocked, i was shocked at the whole narrative of it. boom came the punch, and down i went, straight down with my face falling and hitting the cold concrete."
This attack happened in 2012 in Pittsburgh. B ut the so-called "knockout" or "one hit quitter" game apparently has spread elsewhere.
Videos of attacks posted online.
Missouri, Minnesota, Illinois, Pennsylvania, New York, New Jersey and Washington D.C. -- just some of the places victims have reported being punched on the streets for no reason.
In a few of the cases, the victims died.
"I travel alone a lot like to go to school and go to rehearsals and come home and that's scary."
And just last week in DC, Phoebe Connolly is one of two victims who was punched in the face by kids on bikes, she says for no reason.
"He just threw a hook with his left hand and just got right me in the face. and he said 'wa-pow'," said Connolly.
The juvenile who attacked James Addlespurger was arrested, but the English teacher says there are no winners in the 'Knockout Game.'
Police say a good way to prevent this from happening to you is to be aware of your surroundings.