What stories of Mary Sue have you heard?

There is a boy who is a disaster. One girl in the class, M, likes him, and the other girl, N, is usually the kind of woman who plays better with that boy. Then there is the tearing war. In reality, the friend who said M in the liberal arts class spoke ill of N, and N saw it, so N would unite with the people she played with to isolate M. At that time, I really felt sorry for M, and our monitor didn't care. M once said that if one day, you are all murderers (in fact, I feel that she is very contradictory, right), and then with the teacher's belated intervention, this matter will go away, and the atmosphere in the class will finally be less tense.