What is 'happy slapping'?
'Happy slapping' is nothing to do with being happy. It's a form of bullying where people are attacked and the attack is filmed on a mobile camera phone.
Attackers often share the videos with their friends.
These assaults are not only hurtful and upsetting, but they are also illegal.
Anti-bullying charity Kidscape advise anyone who is attacked in this way to report it to a teacher or adult immediately.
And if you see it happen to anyone else, tell someone as soon as possible, like a teacher, parent or the police.
Any footage found on mobiles could be used as evidence of the attacks.