He grins at you, holdong up the used blue condom. "So, this is the magic one that made you my little brother?"
You nod, then blink as he reaches down and starts to pull it over his penis. "No, Mark! It's gonna change..." You stop and stare, seeing that it is already too late. Mark has stretched the small condom on all the way. He's already looking younger. "Now what's going to happen?"
"See?" Mark shakes his head. "I told you nothing would happen."
You sigh. "Yeah, right. So why are you turning into my twin brother?"
Mark frowns. "What are you...?" His voice breaks in mid-sentence, going up a half-octave. "No! It's not possible!" He runs over to the mirror and gasps when he discoveres it is not only possible, it's fact. The room begins to get fuzzy, and you are suddenly afraid that he has done something to mess up your existance - what if there can only be one of you at a time?
But when the room clears up again, you see that it is now set up with two of everything - twin beds, desks, and dressers for twin brothers. You and Mark are now identical twins.
Mark looks confused, and pulls the condom off. "This is so weird. I'm your big brother, right?? He already seems to be adjusting to your new relationship. "But we're the same age!"
You take the condom from him, noting is still looks curiously well-lubed. "Yeah, it made you the same boy I am, so now we are twins. You lost high school and most of Junior high."
"Huh?" Mark shakes his head and then gives you a funny look. "High school? What are you talking about? We're just in seventh grade!"
You realize there is no point in arguing - especially since your own memories are starting to agree with him. You still rmember what happened and why, but maybe not for much longer. Having a twin is pretty cool, and the family seems nice. Do you want to keep this life or try something else?