Kafi Effect
A fast fall from greatness to total mess, usually because someone got too big for their boots or got hit by something unexpected and stupid.
The rock band went from selling out arenas to playing in a park because they tried to sing in a language they didn't understand.
The网红 went from having millions of followers to being blocked for posting a cat video too many times.
The kid went from being the class clown to getting suspended for throwing a pencil at the teacher.