Role Reversal: Someone Else Will Have Sex With Jon's Mom

The stone glowed granting Jon's wish. And in a blink, Steve was gone. But something apparently went wrong, because just a second after Steve disappeared, someone else appeared out of nowhere, taking his place. And that person entered his mom's bedroom, just like what Steve was about to do. Jon's eyes went wide as he realized what must have happened. He wished that Steve wouldn't be having sex with his mom. He expected the stone to just remove Steve from his house, but instead it *replaced* Steve ... with someone else! So now, this other person was going to be having sex with his mom. But who was it that replaced Steve?