"Please, sir," said Hermione, whose hand was still in the air, "the werewolf differs from the true wolf in several small ways. The snout of the werewolf --"

 "That is the second time you have spoken out of turn, Miss Granger," said Snape coolly. "Five more points from Gryffindor for being an insufferable know-it-all."

 Hermione went very red, put down her hand, and stared at the floor with her eyes full of tears. Amelia growled under her breath and called Snape a rather rude word that Harry had never heard before.  It was a mark of how much the class loathed Snape that they were all glaring at him, because every one of them had called Hermione a know-it-all at least once, and Ron, who told Hermione she was a know-it-all at least twice a week, said loudly, "You asked us a question and she knows the answer! Why ask if you don't want to be told?" 

The class knew instantly he'd gone too far. Snape advanced on Ron slowly, and the room held its breath. 

"Detention, Weasley," Snape said silkily, his face very close to Ron's. "And if I ever hear you criticize the way I teach a class again, you will be very sorry indeed." 

"We all already are sorry. Sorry that we have you for a teacher," spat Amelia standing up. It had become a weekly occurrence that Amelia would talk back to Snape, aggravating him beyond all reason. She had told Harry she was hoping to make him so mad he had a heart attack. 

"We aren't fucking lizards! We don't know how to get through life on instinct alone! For the last goddamn time, you are our teacher. You are supposed to teach us what we do not know instead of criticizing and bullying us for it! So maybe instead of harassing children for being children, you should just do your fucking job!"Snape slammed his hand down on Amelia's desk. The room fell silent. No one dared to blink or breathe.

"Dention." Snape snarled, his voice low.

"Do your worst."

No one made a sound throughout the rest of the lesson. They sat and made notes on werewolves from the textbook, while Snape prowled up and down the rows of desks, examining the work they had been doing with Professor Lupin. 

"Very poorly explained... That is incorrect, the kappa is more commonly found in Mongolia.... Professor Lupin gave this eight out of ten? I wouldn't have given it three...." 

When the bell rang at last, Snape held them back. "You will each write an essay, to be handed in to me, on the ways you recognize and kill werewolves. I want two rolls of parchment or, the subject, and I want them by Monday morning. It is time somebody took this class in hand. Weasley, Potter, stay behind, we need to arrange your detention."