This is scary.  Don't watch it unless you want to be freaked out.  Seriously!  The video is from  a Portuguese TV show - it's a prank, but it would FREAK me out!

I would imagine that somebody might have a heart attack (maybe me!) or at least a full blown panic attack if put in this situation.

Evidently the girl comes into the elevator through a trap door when the lights flicker.

So freaking scary.