Harry Potter and the Methods of Rationality

Into Harry's field of vision, as he turned, stalked a dumpy little woman with messily curled grey hair and clothes covered with dirt. She pointed an accusing finger at the Slytherins. "Explain yourselves," she said. "What are you doing with my Hufflepuffs and..." she looked at him. "My fine student, Harry Potter."

Uh oh. That's right, it was HER class I missed this morning.

"He threatened to kill us!" blurted one of the other Slytherins, the same one who'd called for a halt.

"What?" Harry said blankly. "I did not! If I was going to kill you I wouldn't make public threats first!"

A third Slytherin laughed helplessly and then stopped abruptly as the other boys shot him deadly glares.

Professor Sprout had adopted a rather sceptical expression. "What death threat would this be, exactly?"

"The Killing Curse! He pretended to use the Killing Curse on us!"

Professor Sprout turned to look at Harry. "Yes, quite a terrible threat from an eleven-year-old boy. Though still not something you should ever dream of pretending, Harry Potter."

"I don't even know the words to the Killing Curse," Harry said promptly. "And I didn't have my wand out at any time."

Now Professor Sprout was giving Harry a sceptical look. "I suppose this boy hit himself with two pies, then."

"He didn't use his wand!" blurted one of the young Hufflepuffs. "I don't know how he did it either, he just snapped his fingers and there was pie!"

"Really," said Professor Sprout after a pause. She drew her own wand. "I won't require it, since you do seem to be the victim here, but would you mind if I checked your wand to verify that?"

Harry took out his wand. "What do I -"

"Prior Incantato," said Sprout. She frowned. "That's odd, your wand doesn't seem to have been used at all."

Harry shrugged. "It hasn't, actually, I only got my wand and schoolbooks a few days ago."

Sprout nodded. "Then we have a clear case of accidental magic from a boy who felt threatened. And the rules plainly state that you are not to be held responsible. As for you..." she turned to the Slytherins. Her eyes dropped deliberately to Neville's books lying on the floor.

There was a long silence during which she looked at the five Slytherins.

"Three points from Slytherin, each," she said finally. "And six from him," pointing to the boy covered in pie. "Don't you ever meddle with my Hufflepuffs again, or my student Harry Potter either. Now go."

She didn't have to repeat herself; the Slytherins turned and walked away very quickly.

Neville went and started picking up his books. He seemed to be crying, but only a little. It might have been from delayed shock, or it might have been because the other boys were helping him.

"Thank you very much, Harry Potter," Professor Sprout said to him. "Seven points to Ravenclaw, one for each Hufflepuff you helped protect. And I won't say anything more."

Harry blinked. He'd been expecting something more along the lines of a lecture about keeping himself out of trouble, and a rather severe scolding for missing his very first class.

Maybe he should have gone to Hufflepuff. Sprout was cool.

"Scourgify," Sprout said to the mess of pie on the floor, which promptly vanished.

And she left, walking along the hall that led to the green study room.

"How did you do that?" hissed one of the Hufflepuff boys as soon as she was gone.

Harry smiled smugly. "I can make anything I want happen just by snapping my fingers."

The boy's eyes widened. "Really?"

"No," said Harry. "But when you're telling everyone this story be sure to share it with Hermione Granger in first-year Ravenclaw, she has an anecdote you might find amusing." He had absolutely no clue what was happening, but he wasn't about to pass up the opportunity to add to his growing legend. "Oh, and what was all that about the Killing Curse?"

The boy gave him a strange look. "You really don't know?"

"If I did, I wouldn't be asking."

"The words to the Killing Curse are," the boy swallowed, and his voice dropped to a whisper, and he held his hands away from his sides as if to make it very clear that he wasn't holding a wand, "Avada Kedavra."

Well of course they are.

Harry put this on his growing list of things to never ever tell his Dad, Professor Michael Verres-Evans. It was bad enough talking about how you were the only person to survive the fearsome Killing Curse, without having to admit that the Killing Curse was "Abracadabra."

"I see," Harry said after a pause. "Well, that's the last time I ever say that before snapping my fingers." Though it had produced an effect that might be tactically useful.

"Why did you -"