Jon's sister. Jon's sister, didn't Jon say the Workmen had stolen his sister and effectively erased her existence? And here she was, calling Biff by Jon's name!
"Okay, okay, what the hell is going on here?"
"What?"
"What do you mean what? Don't you notice anything wrong here!?"
She didn't, and after a hesitating glance about she still didn't. Shower forgotten for the moment, Sarah asked "Jon, are you okay? You're kinda freaking me out, bro!"
"I'm not Jon! I'm Biff! There's no way I could be Jon; look around you, girl!"
Any seriousness Sarah had vanishes, and she rolls her eyes, annoyed. "C'mon, Jon, that's not funny. I don't have time for pranks."
"Just, look at this." Biff reaches into the bag and pulls out Jon's student ID, showing it to her and pointing out the image on it. "Does that look like me?"
