Dan awkwardly followed the girl until he found himself standing in the middle of the baby department. Realizing what this meant he opened his mouth to try to convince the girl this wasn't a good idea, but it was too late. As she finished typing on her phone, he found himself deflating, in only a few moments he went from towering over the girl to sitting in a pile of clothes looking up to her.
Looking down he saw that he was unmistakably back to infancy. His body was nothing but tiny and pudgy. An exploration of his mouth with his tongue showed there was only a partial set of baby teeth. And needless to say his package was no longer something he expected to get in trouble for having exposed except for the risk of unexpected peeing.
Easily lifting him out of his clothes, the girl giggled, "Oh wow. It really works. You're so cute now."
She proceeded to carry Dan over to a changing table where she did an impressive job of diapering him. Next he found himself set in front of a mirror while she used him as a dress up doll. Here he noticed his normally straight black hair was now the same bright, curly blonde as the girl. Which had the presumably intended affect of making him look more like her brother.
Between wardrobe changes, he tested his legs and found that, with the help of a nearby stool, he was able to pull himself up to a standing position. Walking proved another matter entirely, after a few unsteady steps at most he found himself back to crawling. He wasn't an expert on babies, but he was pretty sure this meant he must have been no older than a year old but probably not even that.
Eventually the girl got tired of trying different outfits and Dan found himself left in a set of footed pajamas featuring the design of plush bears on his chest and feet. Examining the adorable baby in the mirror, Dan could only hope the girl would be done soon.
But there was something else he thought about while looking at the reflection. His badge was still with the rest of his clothes! Without it the implant wouldn't work! He needed to explain to the girl that they needed to go get it or he'd be in trouble.