Not youtube but man, this vid is one of the funniest and for the poor people involved, the scariest I have seen in a long time.
I laughed at this. I couldn't help it, but man, Im glad I was not one of those on the elevator getting that vicious prank played on me. A person could actually have a heart attack having that kind of prank played on them. I mean seriously. A freaking heart attack.
The link: http://thechive.com/2012/11/26/quite-possibly-the-most-terrifying-elev ator-prank-ever-video/