Penn and Teller Fool Us?

In the t.v show Penn and Teller Fool us , Whats the name of the trick
where a guy has 4 bags and there's a piece of wood with a nail on it
and its in one of the bags and the guy slams his hand on the bag
without the nail in it. Please tell me because there's videos on
YouTube of people doing it and it and their hand goes through the
nail!