After Jon made his wish, a flash of light engulfed Biff's body. When the light faded, there were two identical Biffs sitting on the bed glaring at each other. "There" Jon said happily, "Now that you each have your own bodies, stop fighting."
"How did you do this?" the Biff on the right asked. "Does that stone really grant any wish you want?"
"NO Duh!" the Biff on the left (Tim) stated. "How else would this have happened? Now Jon, give me the stone so I can wish Biff over there in my old body."
Biff exclaimed, "What?! I am not going to go into your geek body! Jon, give me the stone, and I will not pick on you anymore. Plus, I will hook you up with that cheerleader, Jessica; the on you have the hot for."
"Stop!" Jon exclaimed. "I'm not giving either of you the stone. We need to think carefully about what wishes to make next. The stone just doesn't grant wishes, there is a catch. Don't you remember Tim, that wishes are permanent; once you wish something you can only make slight changes to it with other wishes."
"Yeah, of course I remember." Tim said. "My wish will only be a slight change; now hand it over." With that, Tim tackled Jon and grabbed the stone. He quickly yelled "I wish that there was only one of Biff's body, and...", but before he finished, Biff tackled him and the two them started wrestling again. Jon couldn't tell who was who now.
During the scuffle, the stone was knocked a few feet ahead of them. Both jumped for it, and managed to place a hand on it. Without thinking, they screamed, "and I wish that person was me!"