http://www.youtube.com/watch?v=7N5OhNplEd4
Here's footage of a vicious and terrifying prank from a Brazilian candid-camera show, in which victims were put in an gimmicked elevator whose lights went out, allowing a small girl in horror-makeup to sneak out of a hidden compartment and "appear" when the lights came back on, ready to scream at them.
Extremely Scary Ghost Elevator Prank in Brazil
(via Super Punch)