Rule 31. I do not have a Dalek Patronus.
"Mr. Potter, may I ask what you are doing?"
"I think you already did, Mrs. McGonagall" Harry answered cheekily. At the no nonsense look she sent him, he pouted. "You're no fun, Madam!"
She arched an eyebrow. "Excuse me? What did you just say Mr. Potter?"
"I was saying that I would gladly answer you"
"That's better. So, what were you doing?"
Harry was trapped. How was he going to explain what he was doing at three o'clock in the morning wandering through the castle, clearly not asleep as he should be. He had a reason, and a very good one at that. But would his Transfiguration teacher understand it?
Seeing she was growing impatient, he prayed to every god that was that he wouldn't get punished for this.
"Well, you see, Madam, it has everything to do with Voldemort… Come on, not you too? It's just a name, really!"
"I think being sleep-deprived had a disastrous impact on your brain filter, Mr. Potter. If you do not give me an iron-clad reason, I'm afraid you will be in detention for a very very long time…"
"Hum, yeah… So Voldemort. You see, I'm sure he'll try to recruit the Dementors, if they're not already his. And they're my worst fear, so I know he will use them against me. I have Prongs to protect me, that's my Patronus by the way, but I would like something he little more offensive you know. Something that would scare Dementors would be perfect. And then I thought: What could scare Dementors away when they create fear?" He paused for dramatic effect.
After all, it was in the middle of the night, he could be allowed his fun!
"And how did that question led you to wander through the school's corridors at three in the morning exactly?"
"That's the tricky part. Here I was, trying to find something that could scare the Dementors, when I thought that maybe it wasn't even possible to change a Patronus' form. I do not have any books with information on that spell, so I decided to go search for a book. But by then it was already the night…"
"And you could not wait until tomorrow? Well, until today?" Was it him, or had she softened a little?
"You know me Professor, when I have an idea, I've got to take care of it."
"So that's what led you to be out at three?"
"Not exactly." As he said this Harry realized that he had just let pass a formidable opportunity to get away with his latest disregard for the rules as the teacher's glare hardened once again and she gestured for him to keep talking.
"I found the book, and it says that a Patronus can change, but only if the person go through a strong internal personality change. And anyway there was next to no chance that I could see something that could scare Dementors as a protective figure. So that would not work. I went back on my first idea to find what could scare those creatures of nightmares, and the answer became evident! I had to use Daleks!"
"What are Daleks?" McGonagall asked, curious.
"You don't know Daleks? But what do they make you watch on… Forget that. Wizards don't know Doctor Who?" Harry put a horror-struck look on his face. "Anyway Daleks are really bad and if something can scare Dementors, it would be them." He didn't feel like explaining the series to someone who didn't know it. It was complicated enough when you watched it, but explaining that to someone… He shuddered.
"But then I thought that maybe the Room of Requirements could give me the answers I wanted. And I was right too! Look at that Professor! With it, I'm sure we can beat Old Snake face! Expecto patronum."
A Patronus erupted from Harry's wand, but instead of the usual stag came out…
"Is that a pepper pot?" The old witch exclaimed, bewildered.
Harry gave her a pitying look. "Of course not. It's a Dalek. D-A-L-E-K. Dalek. Da-lek"
"I understood the first time, thank you" She said, annoyed.
Harry went on as if she hadn't said anything. "Imagine if we taught this to every first year. An army of Daleks against the Dementors… I'm sure we'd win!"
He had a strange gleam in his eyes and McGonagall didn't like it one bit. It was probably better to put a stop to those ideas before they got out of control.
"Potter, detention. With Filch. For a week"
Harry shrugged. "Do you think I could teach him the Dalek's Patronus?"
"Two weeks Potter. Do not make me take points from my own house or you will regret it"
"I suppose I should go back to my bed then?"
"Yes, you suppose well"
Harry walked to the right end of the corridor.
"Mr. Potter, the Gryffindor's common room isn't in that direction…"
As he walked past her this time, she could swear she heard him mutter something about teaching the spell to his friends. She shuddered.