You watch as the room becomes smaller and your Dad just stares at you then...SNAP! Your shirt begins to rip along with your jeans. You're about the same height as your dad but the changes don't seem to stop. You rush to the bahroom mirror and see your self aging. Your hair begins diminishing until you're left with a receding hairline. Meanwhile hair erupts over your arms and chest. Then your stomach growls and erupts and begins to grow. "Wha-" but you're helpless as your shirt finally rips apart and reveals your new hairy beer belly. Then you feel a strange effect on your body. Your jeans at their limit shred and your left naked as your boxers fall apart.
You now have an array of public hair along with a large array of leg hair. But it's your dick that seems to change you moan as it grows a few inches and your balls form into larger ones. Your butt grows more as it fattens up along with your legs.
Soon you were standing as a middle aged hairy and naked man but turn around to see you weren't the only one.
Your dad had been growing younger as your grew older. His beer belly had reduced by a small amount and his hairline wasn't as receded as before. He even had a beard now instead of his usual goatee. Finally his hair darkens back to its original color of black and the lines of stress and age dissappear from his face. In fact, unbeknownst to you, your dad feels better than he has in ages.
"Will is that you?" Your dad asks looking at you. It was eerie. Except for your hair color you look the same as your dad in fact... you turn to the mirror. The same beard and body is staring back at you. You pull down Dad's boxers and witness the same dick your dick. "Will what are you doing?" He pushes you away and looks embarrassed.
"Um Dad I think we're the same age" you say. Since you were 15 and your Dad was 40 that made the two of you...35!!! The two of you stand naked in his room as you hear Tim yell "I'm home!"