Check out this awesome video of a kid, who is attempting to sucker punch another kid, get his lights knocked out by that same kid he sucker punched.
One of the kids wearing a backpack, most likely leaving school, can be seen in the video walking down a street before another kid comes up from behind him and says a few words before attempting to knock him out with a sucker punch to the head. The two kids then start to grapple with one another trying to get leverage. The two get separated by some of the people in the crowd but then immediately go back to fighting one another.
The one kid who originally was wearing a backpack, pushes the other kid to the ground. While on the ground attempting to defend himself, he gets hit in the head with a vicious knee. He then tries to get up, but the second he starts, he gets hit with a kick to the face, knocking him out cold.