I Would Have Died: SOLID 'Ghost In The Elevator' Prank | Geekologie
This is a video from a Brazilian television show where unsuspecting victims are riding a fake elevator when all of a sudden the lights flicker on and off, and a little ghost girl (who looks like a little sister from Bioshock) appears out of nowhere (actually a secret door in the wall) and you realize you're going to die. Then she SCREAMS at you, the lights flicker back off, and she disappears.
pretty solid prank... i think if i was unsuspecting, i'd have pissed my pants.