Nothing is set in (philosopher's)stone

It is morning at Hogwarts, and Draco and Ron are running in the corridors because they're late for Transfiguration class. In the class, a tabby cat is sitting on a desk. Draco and Ron rush in. Hermione rolls her eyes in annoyance because they're late for class, while Harry tries not to grin, knowing what's coming. 

"Whew! Made it! Can you imagine the look on McGonagall's face if we were late?" Ron shivers at the idea as they look around for a seat. The cat jumps off the desk and transforms into Professor McGonagall, who does not look pleased in the slightest. The two boys are amazed. "That was bloody brilliant!"

"Thank you for that assessment, Mr. Weasley. Perhaps, it'd be more useful if I were to transfigure Mr. Malfoy and yourself into a pocketwatch. That way, one of you might be on time."

"We got lost." Draco tries to explain. 

"Then perhaps a map? I trust you don't need one to find your seats." They quickly sit down and try to disappear for the remainder of the class. Harry turns his attention back to his book. They're going over safety regulations today. They have to read them all and then pass a test at the end of the class to see if they truly learned all the rules properly. The Ravenclaw appreciates this kind of teaching, as it shows their teacher truly cares for their safety and well-being. Potion class, however, became a tragedy instantly, as Harry came to find out later. Later on, inside Snape's potions classroom, the students are chattering, sitting near steaming cauldrons. The door slams open, and Snape comes rushing in, his cape flapping behind him elegantly, making Harry wonder if there's a potion for that.

"There will be no foolish wand-waving or silly incantations in this class. As such, I don't expect many of you to appreciate the subtle science and exact art that is potion-making. However, for those select few-" he looks at Draco, who smiles. "-who possess the predisposition, I can teach you how to bewitch the mind and ensnare the senses. I can tell you how to bottle fame, brew glory, and even put a stopper in death."  Draco raises his eyebrows as he spots his godfather snaring down at Harry, who is taking notes, writing down what Snape said in his lecture. 

"Then again, maybe some of you have come to Hogwarts in possession of abilities so formidable that you feel confident enough to not pay attention." Hermione nudges Harry, finally making him look up at the Professor. Snape then walks to where he can speak to Harry more properly. "Mr. Potter. Our new celebrity. Tell me, what would I get if I added powdered root of asphodel to an infusion of wormwood?" Hermione raises her hand. Harry opens his mouth, but before he can say anything, Snape interrupts him. "You don't know? Well, let's try again. Where, Mr. Potter, would you look if I asked you to find me a bezoar?" Hermione's hand shoots up in the air again. Again, right as Harry opens his mouth, Snape interrupts again. "And what is the difference between monkshood and wolfbane?" 

This time, Harry speaks up before the greasy dungeon bat can speak. "If you'd let me speak, sir. I'd have told you you'd create the Draught of Living Death. And you can find bezoar either in your supply closet or otherwise in the stomach of a goat, as a bezoar stone is a mass often found trapped in the gastrointestinal system, though it can occur in other locations. And finally, there is no difference between monkshood and wolfbane; they're the same thing, which also goes by the name of aconite. Did that satisfy your need for answers, sir?" Sarcasm dripping from his voice. He fully meant that with all the disrespect in the world. 

Professor Snape snares at him, barely hiding his shock underneath his mask of hate. "Well?! Why aren't you writing this down?!" He yells at the class and continues to teach. Harry isn't entirely sure what made this man hate him, but it's clear he has a disdain for him as the lesson goes on. Harry stares at Snape, knowing that he shows dislike for the boy. In the great hall, around midday. The students are all doing their homework. Seamus is trying a spell on a cup.