Mary.
It had to be Mary!
I got up and put on a pair of cargo pants and a shirt. My pants still fit luckily, but differently. They rode a little lower and I felt like my butt was sticking farther back than before. Maybe it was my imagination though.
I went downstairs and saw that Mom and Mary were already up. Mom was going to the store and dropping Mary off to cheer practice.
I decided that one way to tell if Mary had done it was to see if she'd changed herself back. I could 'accidentally' brush against her boobs and see if they were real. If they were, then I'd know she had the medallion now.
"Mom, can I go to the store with you?" I asked.
"Yes," answered Mom, a little puzzled.
I never went shopping with her if I could help it.
I ran back upstairs and put on my socks and shoes. My shoes were too big for me now, but I tightened them up all the way and they were good enough to stay on.
Going out the door, I 'accidentally' pushed my elbow against Mary's chest.