This is sort of the mental image that started it all, though the 23rd's prompt answer is closer to the mental image that gave the idea feasibility.
Prompt for January 26:
Fortune.
Carl's pretty sure he's going to be wide awake for the next couple of days. This battle is... pretty intense, to put it mildly.
They're not in the thick of things, fortunately, but they still found a hiding place within view of the main hall. Of course, it wouldn't have been much of a hiding place without the benefit of Harry's cloak - they probably could have made it work anyway, but only visibly accounting for two people out of five (Crease brought his sidearm, and Bishop... is planning to wing it in the worst case, as far as Carl knows) is a big help.
No one's going easy on anyone, which he supposes is to be expected when dealing with a war. But there are kids out there, fighting and in some cases falling just as hard as the adults. Carl has to give them a lot of credit for sticking it out, especially the kid who's got enough bruises already to suggest he's been tempting fate for a while before this.
He thinks he sees Harry cut across the back of the crowd, at one point, but there's so much going on (even in the so-called ceasefire) that it's hard to say for certain. His re-entry's a little harder to miss, in large part because he's limp and being carried in by a guy who's probably about eight feet tall and five feet wide.
Oh, and because the guy who looks like he's trying to match his giant snake in appearance won't stop gloating. This must be Darth Vader, then; Carl wonders briefly if he's related to the slimy guy who worked for Cosmo.
Everybody just stands there and listens to him spout stuff off for a while, and then the kid with the bruises actually speaks up. And that outrages Darth Vader enough to put a hat on the kid's head and set the hat on fire.
...That's the guy people have been so terrified of the last couple decades? Carl can't help feeling like he's missed something. In any case, the kid's somehow ended up with the sword Harry and his friends were carrying around all spring, and he actually takes advantage of having a weapon and decapitates the snake. Finally, someone in the building's showing a little initiative.
Carl's in the middle of trying to figure out why the kid didn't just go for Darth Vader while he was at it when a shot rings out, and Darth Vader crumples.
The whole place goes quiet, probably in good measure because most of these people have never heard a gun go off in their lives. Carl settles for looking toward the source - an older man in a suit, lowering a handgun and scowling vaguely at Darth Vader's corpse.
"...Oh, for God's sake," Bishop mutters. "How did you get here?"
But the sound carries - the room's got decent acoustics when it's not hosting a battle, and Whistler could call them something a lot more flattering and technically accurate. The man pauses, turns toward the group's hiding place, and smiles slightly.
"Well, this just keeps getting better and better," he says, and Carl goes still. Forget the next few days, he's going to be running on pure adrenaline for at least a week.
"I could ask you the same question, Marty," Cosmo continues, still smirking. "I was simply in the area to attend to some business."
"So were we. Well, for a given definition of business."
"Obviously. I'd be rather surprised if your business were anything like mine, at heart. You might as well come out of your hiding place - I suspect the worst of this mess is over."
"No!" Carl doesn't realize he said anything for a few seconds, until he manages to look away from Cosmo and notices Whistler grimacing and covering his ear. "Oops. Sorry about that. But I'm not moving."
"I don't think he's going to hurt you," Hermione says, looking like she's still processing the last few minutes. "Anyway, you've already given up your position."
"That's beside the point. As long as he's got the gun, I'm not moving." In fact, he's not so sure he'd be able to if he tried.
Cosmo's still smirking, which isn't all that reassuring, but he does at least put the gun on the floor and step away from it. "She's right that you needn't worry, but I concede your point."
As the guys extricate themselves from their hiding place, Hermione says, "...Wait a moment, you shot him?"
"And why not? It's not as though he was doing anything more than pontificating."
"But - but you can't have done that! There was a prophecy, Harry was supposed to defeat him--" There's a meaningful cough from elsewhere in the hall. "All right, or Neville. But one of them was supposed to kill him!"
"Amazing, what you can do when you don't know someone else is destined to do it."
For all he really doesn't want to, Carl can't help but agree with that sentiment.