What's the weirdest or most useless thing you've learned from reading fanfiction?

Reading Harry Potter fics I often come across the word crow and in my language it is often translated with the same word for raven and also for some other species. Then I found this pattern and I don't remember every name in my language. I am more likely to indicate them in English 🤣

And so I was curious if you too had learned something completely random and useless, funny or even useful but that for some reason you didn't know. (For example, in some fics I read real cooking recipes with complete dosages)