All players but one stand in two rows (or sometimes in a circle) with their hands raised, the player that stayed out of this formation is called the statue.
This player must pass in between the two rows and get to the opposite side.
While he tries to accomplish this everyone that's forming the rows slaps him on the back of the head as hard as they can.
The job of the statue is to catch a glimpse of who's going to hit him at any given split second. When he does he switches to the rows and the person caught becomes the statue.
The statue must go back and forth in between the rows until he catches someone.
Of course there is no evident way to prove what the statue saw and if he's right, and that always leads to some heated disputes.