Changing his mind.
That afternoon, a markedly more mobile Harry Potter, having had Care of magical creatures and free periods, was trying to learn memory charms. He couldn't protect his mind, but he could wipe his memory of … certain things instead.
Having to have someone say aloud what he was to forget was an issue. Harry obviously trusted no-one.
A thorough search of the charms section of the library found a talking object charm. Now he had two things to learn.
Harry stared at the speaking object spell and needed some practice. The Slytherin girls of his year came in, in a gaggle, runes having finished for the day, and he had an idea for a stupid, harmless practical joke. Making something speak that would mock the more mock-able girls.
Clearly Pansy, as she was the one in charge.
'My name is Pansy and I'm the boss' Harry wrote on some parchment, and considered what to use.
Something she'd have with her.
He settled on the idea of her ink-well, which was an ordinary ink-well. Harry's would do for a test.
Harry retired to a spare classroom, and locked the door.
Hours of trying to make the inkwell talk failed to make his inkwell talk coherently.
The day was getting late, and his stomach suggested it was time for dinner.
Harry went down to the Great hall, and sat, preparing his silverware to eat dinner.
"Potter?" asked Zabini "Why the sudden interest in food?"
"I'm just… enjoying it more" said Harry, catching sight of some seventh year witches walking into the great hall. They had a certain… presence. Harry watched, silverware ignored for a while. Blimey, he thought.
After dinner he managed a few more hours and got the inkwell to talk.
A little stuffing around the next day with an invisibility cloak, and Pansy's inkwell was charmed.
It started talking in transfiguration last period and Pansy nearly got detention for talking, and her friends got a case of the giggles. It was, Harry realised, the first time he'd seen the Slytherin girls in a good mood. It was an odd feeling seeing Davis and Greengrass smiling at all.
Harry went to a carefully chosen out-of-the-way room that evening and started work on making a parchment that would talk, and tell Harry what to forget. He'd chosen a parchment because he could have it in his book-bag easily, and he could burn it afterwards.
The parchment wasn't quite talking coherently by curfew, so Harry left and went to dorms.
Zabini raised an eyebrow at Harry as he entered the dorms. Harry smiled toothlessly at Zabini.
"Someone charmed Pansy's inkwell to talk, and Pansy nearly got a detention" said Zabini.
"We were all there" said Harry idly.
Nott was lying in his bed starting at Harry like he feared Harry was going to hex him.
"Boo!" exclaimed Harry and Nott shuddered.
"Oh Potter, that was gratuitous" said Zabini.
"Nott is still human, and has all his limbs." said Harry, smiling again.
Zabini shook his head. "Harry Potter, dark lord."
"Oh please" said Harry "As if I would do that. Black robes, high collars? Not my style at all. I'm just trying to stay alive, given that people keep trying to kill me."
"Not so many recently" said Zabini, probing for information.
"Even fanatical followers of the former dark lord can learn, apparently." said Harry blandly.
"They're mostly dead" Zabini said with a tiny smile.
"I guess that's like learning." said Harry, smiling broadly and getting changed.
Crabbe and Goyle didn't try anything, and Harry charmed his curtains imperturbable, soundproof, hex-proof and went to sleep.
Harry's next day had blessedly nothing in his schedule, so Harry took a book-bag of books he needed to never be caught with, and went to his fairly-secret room and sat down to work. The books went into the fireplace and were incinerated with a decent incendio curse, and he vanished the ashes.
He got the parchment talking properly, started the fifteen-second timer on the parchment, and finally cast Obliviate on himself. He woke with a strange feeling like he'd forgotten something. There was a parchment in front of him, with his own writing on it.
'Congratulations me. If you're reading this, you've successfully obliviated yourself of some awkward memories. Incinerate the parchment it's the only remaining evidence. And do it quickly or the whole plan can fail.'
Harry dropped the parchment on the floor and incinerated it. Plenty of time now before dinner to sneak out a window on a broom, while wearing an invisibility cloak and find that tower with the mirror of Erised. He quickly forgot ever reading or incinerating the parchment.
Harry packed up his much emptier book-bag, and went back to dorms. He dumped his book-bag, put on practice clothes, stuffed in his invisibility cloak under his clothes and went out to the quidditch pitch, to pinch a broom to use.
The Nimbus two thousand and one flew beautifully and Harry headed up over the school.
None of the decorative towers over the Great hall had a mirror in them, but Harry found it, finally, in a decorative looking spire near the Ravenclaw tower. The window opened to alohomora, and Harry landed, took off the cloak and looked into the mirror. He saw himself, eating a cracker with some cheese on it. It did look quite delicious, and he'd missed lunch. Harry concentrated on ignoring his hunger and the mirror shimmered, and an image formed. Harry, smiling, standing while a witch, kneeling in front of Harry did something with her head level with Harry's lap. Mirror image Harry winked and took an apple from his robe pocket and bit into it, eating with obvious relish.
Harry was confused. He'd wanted revenge as an eleven-year old, and now his deepest desire was… a snack and some oral sex. Why?
Then it hit him… he'd had his revenge. He no longer desired it, he possessed it. He definitely felt in his belly the lack of lunch. The business with wanting a witch near his bits… he was unsure about that. The witch stood up, and dropped her robe off, and rubbed against mirror Harry's body, and Harry was impressed at the sight of that bum. It had his pants getting quite tight, then… the image in the mirror reformed and Harry was… shagging someone in a bed. Their hair colour was odd, sort of a grey like the mirror of Erised didn't have a colour to draw, but Mirror Harry made eye-contact with Harry and mirror Harry winked again. Harry gazed for ages at Mirror Harry's shagging, getting a decent look at wobbling boobs on the witch. Harry finally remembered Dumbledore's warning about the mirror; that men had died from staring at the mirror and forgetting to live. His stomach grumbled and Harry fled, invisible. He went to the Hogwarts kitchen and got a plate of sandwiches, sat at a small table and ate. They were, he was sure, the nicest sandwiches he'd ever eaten. Which was odd, but maybe the house elves had just done a really good job today.
That evening, before bed, he took out his tarot cards and tried a quick prediction.
The Fool. Bollocks. Unwise actions causing tragedy. Or alternatively a young man setting out in the world. Probably the former knowing his luck.
After savouring breakfast which had Harry smiling blissfully, he went to Divination first period.
They had to start a dream diary. Which was a bit embarrassing, as all Harry could remember from yesterday was … dreaming of snogging and wetting his pyjamas. Harry wasn't expecting Professor Trelawney to approve of that, it didn't seem… very divinational. Apart from predicting that he'd probably have a similar dream again soon.
History of magic gave Harry time to think of a plausible sounding dream for the diary, and then double potions with Snape. Who gave him a P for a perfectly good potion.
Harry watched the seventh year girls as they came to dinner that night. They had… development, far in excess of the fifth or sixth year girls.
The meal appeared on the table, and Harry started serving himself, and noticed, as he looked up-table that Greengrass was whispering to one of the sixth year girls, it looked like she was talking to the prefect, actually. And gave Harry a dirty look. She clearly hated him for some reason.
Harry pushed through the crowds of Slytherins heading down to the dungeons, being given space to move mostly, for no obvious reason, and he was most of the way to the common room before the sixth year female prefect Greengrass had talked to stepped in front of him and pointed to a doorway.
"Go in" she said. Harry vaguely recalled she was Fawley.
Harry sighed and entered a disused dungeon room, which looked like it might have been a classroom at some point "Yes?" he asked.
"Greengrass tells me you had a fit on the train, needed medical attention. What follow-up have you had?" asked Fawley.
"I don't need further treatment" said Harry, peeved. Hovering behind the prefect, peering around the edge of the door was Greengrass.
"Greengrass?" Harry said loud enough to call her over. She drew her wand, cast a shield and advanced, looking nervous.
"Have I threatened you before?" asked Harry "My memory is a little haywire."
"Your eyes went red" said Greengrass "Like you-know-who."
Harry sighed, and flicked out his wand "Obliviate!" he cast, and hit both Greengrass and Fawley.
A second flick of his wand closed the door.
He pointed his wand at Fawley and carefully said "You never heard Daphne Greengrass mention that I had red eyes. You questioned me about my illness on the train, and I told you I needed no further treatment. Greengrass… was happy to hear it. You need to go to the common room now" Harry said with a grin.
Fawley nodded groggily, and stood by the door.
Harry pointed his wand carefully at Greengrass and said "You never saw Harry Potter have red eyes. Harry Potter winked at you, and you were shocked, you need to go back to your dorm room and study."
Harry opened the door with an 'alohomora.'
Daphne nodded groggily and left.
Harry closed the door to the room again and rummaged in his pocket. A roll of parchment and a self-inking quill, a rickety conjured chair and the dirty dingy desk already in the room, and Harry started writing runes out, and enchanted the scroll to talk. To tell Harry…
'You were asked about your illness on the train by prefect Fawley, and admitted you had been ill and needed no further treatment. You did not obliviate Fawley, You did not obliviate Daphne Greengrass. Daphne Greengrass was alarmed because you winked at her. You will not remember incinerating this parchment' finished Harry, and several hours later the parchment talked.
Harry tapped the parchment to start the timer, and cast an obliviate on himself.
Harry blinked and saw a rune-covered parchment on a worm-eaten table in front of himself.
The parchment was covered in runes, and magical symbols, but the bottom simply said "Hi me, incinerate the parchment now."
Harry incinerated the parchment and vanished the sooty scraps, and opened the door, into the dungeon corridor. A trickle of lost-looking first-years were wandering left, and Harry joined them, soon becoming their leader and opening the secret stone door to the Slytherin common room.
As he crossed the common room towards his dorm room he wondered, what had he just been doing in the old classroom. Harry mentally shrugged, he had a few holes in his memory. He also had a Transfiguration essay to write.
Theodore Nott shuddered at his desk as Harry walked past to his bed and table.
Harry wondered why Nott feared him so. It wasn't like he'd murdered Draco Malfoy or anything.