One suggestion I have (similar to another person's) is the mushroom. Instead of growing large enough to destroy a city, however, I propose one of two effects:
1. Mario mushroom, it simply increases their size by (based on how it looks in the games) about double.
2. she grows a male appendage, either futa or pure male, you can decide.
Thanks for your support!
I have been thinking about it and tried generating images with extra size without success, and after seeing the reactions about the futa ingredient I decided not to add it.
I already have in mind the 2 (or more) remaining ingredients, I only need to be inspired to write the stories and generate the images!