Screen Smasher

Need a reason for a fight? How about your shattered screen?
This is a cool joke to play on your friends. Start the counter to set the trap, then hand them your phone and let them do what they like - surf, play games or look at pictures. When the time comes the screen will "break" upon a finger touch, with a nice cracked window effect.
A proper candid camera prank, all you have to do is say "Gotcha!"
Have fun!