Jungkook, one of the seven most popular boys in your school, does this to you:
Wwyd?
So the story here is that Jungkook has known you from when you were little but you had an accident and part of your brain was damaged. You can't remember him at all, but he remembers you and has a crush ever since. Now he's not that quiet boy anymore, he's flirtatious and confident. This idea is very common lmao