Crushing a can of beer or soda with your forehead.
Often starts by a drunken man wanting to show how tough he is, and hey, he just HAPPENS to have an empty beer-can in his hand...
Sometimes it's a macho thing, and sometimes it's Played for Laughs.
The most frequent variation involves the can being full, with resulting cranial trauma.
In Real Life this could result in a concussion, especially if [...] [tvtropes.org]