DA practice was over, and Harry and Luna were the last ones left, cleaning up the equipment. They could ask the room to vanish the targets they had been practicing aim on. The problem was it would give them completely new targets next practice, and reset the scoreboard (helpfully provided by the room with each DA member's name and number of center-circle hits on it). That had been fine when everyone had terrible aim, even with the easy color-changing charms Harry had taught first. Nobody wanted to be reminded how many times they had missed the targets last practice. Except Angelina and Katie ... Harry thought their hand-eye coordination from playing chaser translated well to aiming small bursts of light at stationary targets. Angelina and Katie had been top of the group since Harry had started the DA on aiming. But now the group was getting better about actually hitting the targets, and the DA had gotten a bit competitive.
Angelina and Katie was still top of the scoreboard. But Neville was quickly gaining and Fred and George were closing the gap, too. They had found a way to permanently color Katie's center circle for half the last practice, so her hits did not register on the magical scoreboard. Katie had yelled at the twins about dirty rotten cheaters not that this really matters anyway and you better not do stuff like this in our next match and give Madam Hooch a reason to give Gryffindor a penalty. Everyone paused to watch the fireworks, and Harry used the distraction to quietly vanish Katie's scoreboard and ask the room for a new one. But despite consistently hitting the center for the rest of practice, Katie was still slightly behind the twins when Harry called practice over. Angelina's name, with Katie's name hovering down near Neville's, had risen to the top of the scoreboard. There was a shimmering around Angelina's target, perhaps she had thought ahead and taken steps to prevent Fred and George's pranking. Or perhaps she had been tipped off. George was being slightly more friendly than he was with his other team members...
Hermione had pointedly left for the library as soon as practice ended so she didn't have to watch Ron and Lavender leaving hand-in-hand as usual. Harry had used the map to let the rest go in twos and threes, making certain the coast was clear of Inquisitorial Squad members and Slytherins in general. Luna had lingered after everyone else, chatting with Neville then helping Harry read the map.
"Can't let them go that way, Harry, Fawcett's coming. I think she's secretly a Slytherin."
"Luna, she's in Ravenclaw."
"But I never see her in the common room. And do you see her in the Gryffindor common room?"
"No"
"So that leaves Hufflepuff or Slytherin. And if she's secretly a Slytherin, we should wait until she's gone. Just in case, right, Harry?"
Smiling, he waited until Fawcett was two corridors away before sending out the next group.
Finally there was nothing left to do but clean up. So Harry and Luna were using hovering charms to move each target to the side of the Room of Requirement where they wouldn't be in the way for next practice. Harry was about a quarter of the way down the line when Luna paused, setting down her target by the wall.
"Don't you think we should do something about all the wrackspurts in here, Harry? They were really hurting Zacharias Smith's aim this practice. I saw Susan looking a little confused after she missed three in a row, too."
Halfway across the room with Terry Boot's target floating in front of him, Harry snorted. "I don't think Zacharias needs wrackspurts' help to miss the targets, Luna."
"I think everyone would really benefit from not being distracted, Harry." She frowned slightly. "And don't you say the little details are important? Wrackspurts can really hurt your concentration, you know."
"Yes..." Harry paused, concentrating on tucking Terry Boot's target safely between two other targets. Once it was deposited, he turned towards Luna. He searched for the right phrase for a moment, then tried "Wouldn't it be difficult to get rid of all of them? I won't make people stay in the Room of Requirement more than we already do. I know Malfoy's getting suspicious..."
Luna smiled, dreamy as usual but perhaps with a hint of smugness. "They are not hard to get rid of, Harry, not at all. Daddy showed me how to get rid of a wrackspurt infestation ages ago. We can do it right now, I'll show you. You just make a spiral with your wand where the wrackspurts are hovering. The incantation is incumbo." She twirled her wand slowly, exaggerating the motion. "Like this, Harry."
He still seemed dubious, but tilted his head and made a spiraling motion in the general direction of the ceiling. "Incumbo?" He raised his eyebrows at Luna, who nodded encouragingly and pointed her wand towards the corner Harry. Making an exaggerated spiral, she carefully pronounced the incantation "Incumbo." She nodded, satisfied there were no more wrackspurts left in that particular corner. "Just like that, Harry."
Harry quietly repeated "Incumbo" trying to match her emphasis, then nodded back.
She dropped her wand with a clatter to clap enthusiastically. "That's it!"
Harry turned and walked towards the next nearest corner, repeating the incantation and waving his wand the way she had. Luna twirled to pick up her wand, then turned to take care of the other half of the room. Harry walked around the edge of the room, waving his wand a bit carelessly, while Luna worked her way slowly along her wall, swaying from side to side as she repeated each incantation carefully, enunciating each syllable. Every few steps she turned and inspected her work, making certain every inch of the crease between the ceiling and the walls was cleared. After she walked a few feet, the Room of Requirement seemed to push in on itself, trying to be helpful. Harry was a bit surprised, but Luna just turned and gaily sang a "thank you!" towards the center of the room.
They met on the other side of the room after a few minutes, rather closer to Luna's side than Harry's. She tucked her wand behind her ear and stuck out her arm. Harry was nonplussed for a second, having not shaken hands in months, before switching his wand to his left hand and gamely offering her his right hand. Luna took it in both of her hands, pumping it up and down, before abruptly turning back to the remaining targets in the center of the room. As she walked back towards them, a lilting "Thank you, Harry! I'm sure Zacharias will appreciate it!" floated back towards him. Smiling, Harry shook his head, and followed her to finish putting away the targets.