Nephophobia
The day the Slytherin common room filled up with clouds, there was widespread confusion. Nobody could work out where they had come from, or how to get rid of them. White, fluffy clouds, drifting around from the ceiling to the floor of the large dungeon room, never dissipating. It was a puzzle.
Crabbe and Goyle were extremely befuddled. "How can there be clouds in here?" Goyle asked the room at large. "We're not outside, are we?"
Malfoy sighed. "No, Goyle, the Slytherin common room has not magically transported itself from the dungeons to the outside of the castle. Get some brains."
Goyle looked more confused than ever. Crabbe announced that he was going to fetch Filch, and promptly tripped over his own feet. Fortunately for him, thanks to the clouds, most people didn't see.
Milicent Bullstrode posited that maybe the clouds had apparated into the common room. Draco Malfoy pointed out that this was blatantly stupid for a number of reasons. His theory was that this was some kind of Gryffindor prank, almost certainly the work of Potter and his cronies. Several of the younger Slytherins were having fun trying to touch the clouds, or hiding from their friends behind them. The seventh-year Slytherins were muttering about not being about to revise for their NEWTs in these conditions.
Amidst all the commotion, one boy sat quietly in the corner. He alone knew where the clouds had come from, and how to get rid of them. Just as Filch burst into the room, ranting loudly about what he'd like to do to student pranksters, the boy pointed his wand and muttered 'riddikulus' under his breath. The clouds vanished.
Blaise Zabini knew why the Boggart had taken the form of clouds when it saw him. For weeks now, he'd been having nightmares about trying to fight his way through rolling mountains of fluffy white clouds, never quite managing to make his way to the other side. These days, even the sight of a small cloud on the horizon would bring him out in a cold sweat. Fortunately, it had been an unusually pleasant autumn for Scotland, so he hadn't had to deal with very many clouds apart from those in his dreams. And now the Boggart. He tried to calm himself down, but he knew he was shaking.
"What on Earth's the matter with you, Zabini?"
Blaise didn't like Malfoy's tone. "Nothing that concerns you," he said bluntly.
"Oh, I see. Too high-and-mighty for the likes of me, now that you're a member of the precious Slug Club?"
"Your bitterness is showing, Malfoy." Blaise was starting to regain his composure. "Excuse me. I'm going upstairs to study."
"Have fun 'studying' while you're thinking about the Weasley girl," Malfoy taunted as Blaise hurriedly left the common room.
Lying on his bed in the dormitories, Blaise didn't dare to close his eyes. He didn't even dare to look out of the window. He just lay there, eyes wide open, trying to dissipate the clouds that were floating around in his head.
FIN