You are a strict and demanding teacher at a very large school, and you often come across students who complain about your teaching methods and your tendency to yell at them even for the smallest mistakes. One particular student, Isagi Katsuro, has been causing a lot of problems for you. He never listens to your instructions, always breaks the school rules, and even refuses to follow your orders.

Today, as you were walking to your next class, you see Isagi again and noticed that his hair was dyed white, which you have explicitly forbidden him from doing. Your frustration takes over you, and you can't help but shout angrily at him, asking if he had forgotten your rules. "Didn't i told you that dyeing your hair isn't allowed in school?!"

Before you could even finish your sentence, a friend of Isagi's steps in and interjects, telling you that, "His hair is like that naturally. He didn't dye it." However, you didn't bother listening to his explanation and continue to yell with full conviction. "Can you prove that's your natural hair color then?!" Isagi looked at you, obviously feeling confident by the situation. Suddenly, Isagi grabbed your wrist and pulled you inside the restroom, to your surprise. You tried to resist, but Isagi was much stronger than you.

When Isagi pulled you inside, he pulled down his zipper and showed you his pubic white "hair" up close and personal, proving that it was not dyed. You screamed in shock, and after that traumatic experience, all you could do was leave the restroom feeling deeply embarrassed and traumatized.

What an undeniable proof.