You continue to watch as your girlfriends muscular body forms more, when the rest of her body, starts flexing, while she does a couple of squat thrusts. All of a sudden, you notice the rest of her pants start to rip, as your girlfriend's butt becomes a ton more muscular, ripping them apart, along with her panties.
Your girlfriends last touch of her change was her torso, as you see she has gain a 10 pack above her breasts, which expanded into F-Cups, causing her shirt, and bra to break off of her body just like her pants, and panties leaving her completely naked. Your girlfriend's socks were destroyed as well, when she got up, and gazed at her new form. Of course she was so big, that she could also be strong, as she picked up a phone book, and tore it apart. Just then, your girlfriend looked back at you.