Quidditch Practice in Detention is (Rarely) a Good Idea
"Oh, shit, Prongs!" Sirius Black whisper-shouted, flinging himself across the desk to snatch up the jar of pickled Peruvian tree frog James Potter had just deliberately knocked to the floor.
"What the hell is wrong with you, you stupid git," Sirius muttered, delicately placing the tree frog back in its jar, and half-heartedly clamping the lid back in place, deciding that it would probably stay closed. And if some student picked it up without realizing the lid was askew, and got a face full of pickled frog guts, well, so be it. Hopefully it at least would be a Slytherin.
"Merlin, Prongs, we'll be here an extra hour if Slughorn sees you on purpose dropping his stupid ingredients. We're meant to be learning respect for Potions, my dear boy." Sirius dropped his voice, and wagged his finger at James, doing a rather poor impression of Slughorn. Somehow, he never could twist his lean face into anything approaching the jowly countenance of their Potions Master.
James smirked. "Padfoot, you twit, since we've unfortunately been forced to skip tonight's training, as Quidditch captain-to-be, I'm merely helping you hone your reflexes. Catching that jar was practice, obviously."
Sirius almost picked up a jar of his own to fling at James' grinning face. "You stupid bleater, I'm a beater. I don't have to catch anything."
"Fine. Transfigure something into a bat, and I'll toss these at you." James curled his fingers around a pair of jars, containing, Sirius realized, dried essence of dittany, and something reddish-pink that pulsed faintly in some kind of syrup.
Sirius was terrible at Potions; something about adding finicky bits to other finicky bits while counting backwards from 1000 by 12s while standing still for hours made him want to burst out of his skin, and float away from the damp and the fumes of their dungeon classroom. Thus, he had absolutely no idea what funny or disastrous thing might happen if he were to shatter these jars. He was only handling them because Slughorn had set him and James to re-writing the faded labels on the pile of dusty jars, after the pair of boys had spent their previous Potions lesson making Fire-whiskey infused hot chocolate in their cauldron, and surreptitiously handing out cups of it to their classmates.
James quirked his eyebrows, and hefted the jar of pinkish fungus, which shifted wetly in its gelatinous mixture, sending a shiver of anticipation up Sirius' spine. It would make such a fucking mess when it smashed.
Sirius scooped up his quill and whispered Avenir Baton, holding the dimensions and shape of a Beater's bat in his mind, drawing his wand down the length of the quill. Silver light rippled in the wake of his wand, and suddenly his quill was 3 feet longer, and made of wood. Sirius gripped the bat with both hands, and bent his knees, ready to pummel the jar tossed by his best friend.
He shuddered slightly, feeling the excitement of this idea in his shoulders and the pit of his stomach; because Sirius Black was never happier than when he was turning things on their unsuspecting heads. He loved disorder and cacophony and chaos, and doing this would create all three of those things, and the outcome of this was unpredictable, and it was potentially dangerous, and it would demonstrate the full measure of his disrespect for Slughorn, who always looked at Sirius wistfully, as if he wanted to be him, or have him, or own him.
Sirius licked his lips, completely lost in the deliciousness of this idea, beyond ready to piss off Slughorn, supremely uncaring of the consequences that would result from this. "C'mon, Prongs," he growled, staring fixedly at the jar in James' hand, ready for the pitch.
Sirius, focused as he was, missed the consternation flash across James' face, as James reconsidered this idea. Most of the time, James felt like he and Sirius lived inside each others' heads, and that was wonderful, obviously. But sometimes, at moments like this, or other times when Sirius suggested pranks that would be more painful than they would be funny, or when Sirius continued torturing Snape or some other Slytherin long after James had decided that he himself was quite finished being a bastard, James realized that he and Sirius were not quite the twins everyone believed them to be.
Sometimes, when Sirius disappeared into a place inside his own head that James could not and did not wish to follow him to, it seemed like Sirius was slipping into his family inheritance, and was becoming someone who deserved the surname Black. But, after 5 years of being Sirius' friend, James knew how to send him there, but he also knew how to bring him back.
James grinned at his friend. "Ready, Padfoot?" he whispered, and tossed the jar.
Just before Sirius made contact with the jar, James Vanished it. Sirius, carried by the momentum of his swing, kept spinning, and made a full circle before stopping unsteadily and glaring at James.
"What the he-"
"Augumenti!" James roared, and shot a spray of freezing water at Sirius, completely drenching him.
Sirius, his long hair dripping into his eyes, and his robes clinging to his frame, raised the bat, and advanced toward James.
From the front of the classroom, Slughorn, who could no longer ignore the antics of the Gryffindor boys, shouted at them to behave, and heaved his ponderous form up off his seat to tell them off.
"Padfoot, mate," James held his hands out toward Sirius, smiling nervously. "Again, as your Quidditch captain, I was just testing your, um, abilities, you know, to dodge."
"No, Potter, I get it," Sirius replied, baring his teeth at James, and stalking down the aisle toward his friend. "I respect what you're doing for me. So, c'mere and stand still, and I'll practice my Beating abilities some more. With your head."