you were a talkative troublemaker and Scaramouche was the class president.

while the teacher has gone out of the classroom for a while, she put Scaramouche in charge. Since the teacher was gone, you took the chance to cause some trouble.

you took out a page from your notebook and wrote "hey loser" and crumpled it amd threw it at Scara's head, just to mess with him

"Who threw a piece of paper at me?!"