The "Angry German Kid" is the main character in a viral video, depicting a young teen having a violent temper tantrum when things don't go his way in a video game.
In reality, the video was staged, and was intended by its creator (the teen who plays the Angry German Kid) as a parody of what many people feared, that violent video games would lead to gamers being violent. It is one of a series of videos made by the teen, who parodies other societal phenomena such as the "gangster". However, when the video was played on German TV, the TV producers lied and told the audience that this was an unstaged incident, secretly taped by the boy's father.
In Japan, he is referred to as the “KeyBoard Crusher” or “KBC”.
http://knowyourmeme.com/memes/angry-german-kid-keyboard-crasher