My fiancé and I recently got engaged, and, on first notice, everyone was really happy and excited for us. But then, my MIL started "jokingly" saying that I should watch out because she might just show up to the wedding wearing a white dress. These were her literal words, in the MIDDLE of our engagement dinner. My fiancé tried to divert the topic of the conversation, kept telling her that everyone knew she wouldn't dare (as a warning). But it's been a week, and she's been sending me screenshots of white dresses she's found around that she "might want to wear to the big day!" What should I do? I'm starting to get really angry, but I don't want to start an argument with her either. This woman is very dramatic, and I just know it will influence her mood throughout the whole wedding planning.