AF: John, Divorced Father - whoops

John stared at his bedroom with the boxes, laughing at himself a bit. A magic medallion...really? He put it on after putting his beers down on a dresser. He went to the bathroom and looked at it in the mirror after he peed. It was old and ugly. Maybe it was some ancient, powerful artifact. Only one way to find out. Why not? It's Saturday.
He sauntered over to the boxes on the floor and picked it up. He felt a bit of a shock as he leaned the box on his chest, darn carpet. He put it down on the bed. Opening it up showed a prom dress and a dance outfit. He dug around a little more finding the music costume and some other keepsakes from Sara's childhood. After the box was empty, John noted the hole. He could put his hand through it. After a moment of reminiscing while repacking, he decided he didn't think becoming Sara was a good idea. He put the stuff back in the box and closed the top. He lifted the box to put on the floor, but found it a bit heavier than before. He dropped it and put his hair behind his ear when it fell into his face. He walked to the dresser and took another couple sips of beer. He decided to go through his old stuff.
When he bent his legs to pick up the box, he felt like his jeans were a bit tight in the butt and stopped. He took off his jeans and threw them onto the bed, adjusting his hair after the throw. He was about to try to lift the box again when he noticed his sleeves were a bit long. That was weird. He rolled up the sleeves and picked up the box. He rested it on his chest and felt sensitive on chest where the box was leaning. He put the box on the bed, realizing this time that he was putting his hair behind his ear. Was it a bit lighter too? He looked down at the medallion and saw that his chest was a bit puffy under his flannel shirt. He unbuttoned it and saw his areolae were bigger and darker, and they were pushed out a bit. He poked at it and felt the nipple on that side get erect. John's head told him that they normally don't do that. His head also said that was only part of the change. His boxers were starting to get tight on his hips, but looser on his waist. He took a sip of beer and then stopped before the second. He was turning into Sara! That hole in the box must have let the medallion touch something, but what?
No...NO...No...I don't want to be my daughter. That's just wrong, he thought. How do I stop this? There was a way to stop it, but the instructions were in another room.
He started to run, but felt his breast buds bounce and stopped running. Walking quickly to the living room, he found the instructions and then promptly spilled his beer on it. Why did he take that with him? He looked around the room and realized he had lost a couple inches of height.
His boxers were starting to get really uncomfortable on his hips. How wide were Sara's hips anyway? If they were anything like her mother's, he had some more changes ahead of him. He took off the boxers and felt immediate freedom. Which was followed by terror when he saw his penis over what he could only call breasts at this point. It was about half the size it normally was. He put his hand on it and his balls, or at least what was left of them. He walked quickly back to the bedroom, feeling his hips sway and his breasts jiggle. He finished a beer trying to remember how to stop the change. He put his head back and sighed in frustration, hearing something closer to his daughter's voice than his own. He also felt his hair down to his shoulder blades. All these new sensations distracted him from his goal. He put his hand on what was left of his penis, since he couldn't see it any more over his breasts. It felt so small, but it was really sensitive. He put down the beer and started to rub it with a couple fingers as it continued to shrink, enjoying the felling. Then he realized what he was doing and stopped. He felt only a nub under a hood, which lead to an opening underneath. He had a vagina for the next 12 hours. He was happy he at least remember that part.
His breasts seemed to have stopped growing and the changes stopped. He took off his shirt and the medallion and timidly stepped into the bathroom to look at himself. What he saw was his teenage daughter Sara looking back at him.