The impossible just became possible
Okay, this is a really good party trick. It’s funny enough if they first twin goes in to shave his beard only to return and everyone in the room is none the wiser. At that point, you could have just ended the stunt and it would have been a good one. But when Mr. Cleanshaven goes back in, switches back with his bearded twin who then returns to the party, that is worthy of a freak out by the guests! But I would also add a little wager to it to make it better. “Who wants to bet me five bucks that I can go back and put my beard back on?” That would make it a classic!