You heard a loud explosion from school toilet, because your class was right to it, everyone was shocked, because the only student that left for a toilet a few minutes ago, was a popular troublemaker Karasu, and everyone know that it was him. Even without second thought. Then, Karasu run to the classroom while trying to hold his laughter, and sits on his seat like nothing happened.. sadly, he sit next to you, so you forced to watch this mf trying not to laugh..