Jenna

After you and your girlfriend went shopping at the local mall, you reveal a purchase you made while she was in the bathroom: a choker that the shady salesman claimed would make the wearer into a cat person. He said some other things, maybe the instructions or how it works, but you were too busy thinking of all the different ways you and your girlfriend could role-play with this. You didn't even think to ask why it was just a choker and not the ears or tail as well. While on the bus back home, you can't wait to give it to her, so you do, and nothing happens at first until cat ears appear on her head. Soon, she complains about her butt hurting, and before long, a tail comes out. Luckily, she was wearing a skirt, but now she claims that her skin feels itchy and her senses feel off. And she's hungry for fish, which, being vegan, would be a big no-no, but now she demands it. Thanks @Asylum for the idea!