Somehow, Megumin managed not to blow up Hogwarts in the three weeks between the first Quidditch match and the Halloween Feast. She even managed to retain her wand for most of that period, only losing it for four days when she got "creative" in transfiguration and transfigured her mouse into an exploding snuff box after doing it properly several times.
That wasn't to say that Megumin didn't manage to create a large explosion. Somehow, giant tadpoles had begun to be found in the lake, and were proceeding to eat all the fish. The mermen were complaining, and there were several frogs the size of hounds hopping about the shore. Either the giant frog kept escaping from the third floor corridor, or more likely, its' spawn were.
In a fit of what can only be described as a complete failure on several levels of forethought and administration, Argus Filch set Megumin and the Three Stooges to "eliminate" as many of the giant tadpoles and frogs as they could from the lake.
"Use this net, and scoop out as much of the damned stuff as you can. Just toss them in those barrels," Filch ordered the four one evening.
"Can we use our wands, sir?" Draco asked, not relishing the idea of touching slimy frogspawn or tadpoles, even with a net.
"I don't care how you bloody well get rid of them, just do it!" Filch ordered, then stomped off to the rest of his duties.
"I think we should spear them!" Dust declared, and promptly dug out a large fishing spear from the gear that Filch had left piled on the lakeshore after putting on a pair of waders, going out into the icy water. A moment later, he had easily skewered a large tadpole, holding up the wriggling thing on the end of his spear. "See? It's dead easy!"
"I can do that!" Megumin declared, and eagerly scrambled out into the water to try her hand.
It was, however, much harder than it looked, and she only managed to splash about a bit.
"You've got to factor in the refraction of the water," Dust told her, his spear darting out to get his fourth tadpole. "And aim where the tadpole is going to be, not where it is."
"Hmph. This is dumb," Megumin complained.
"Flipendo!" There was a sudden spray of water, and Megumin shrieked as she was doused.
"Sorry," Kazuma called, grinning and waving at her. "Just doing it the proper wizarding way."
Indeed, Kazuma's spell had blasted a tadpole out of the water, and he scooped it up with the net and tossed it in the barrel. "Point to me."
"What?! That's not fair!" Megumin complained. She hurried out of the water even as Draco and Kazuma hurled various minor jinxes and hexes at the giant amphibians.
Megumin pondered this for a bit, then pointed her wand at the lake. "Confringo!"
A deafening report and a massive geyser of water immediately doused all four students. It also sent a positive rain of tadpoles falling around them, much to Megumin's delight.
"Are you bloody m-mental!?" Kazuma demanded, his teeth chattering. "Y-you're g-going to kill us a-all!"
"I dunno, Kaz, that seemed pretty efficient to me," Dust remarked, apparently unfazed at the dousing.
"Hmph. I scored more than you," Megumin said, then pointed her wand back at the water.
Before she could manage to cast another spell, a very angry looking merman stuck his head out of the water. Raising a webbed fist, he proceeded to harangue the four wizards in his alien tongue.
"Well, you wanted us to get rid of the tadpoles, so I did!" Megumin argued, despite not understanding a word of it.
Before she could manage to cast another spell, Hagrid thundered up, puffing and blowing. "What the bleedin' hell is going on? Megs, yeh can't be tryin' teh blow up the whole lake!"
"No, that is why I kept my first explosion very small," Megumin explained. She pointed at the merman. "Tell him to get out of the way, my next one will be much better!"
"Oh hell. Look, no more wands! This is a detention, yer supposed teh be punished, not terrorize the poor merfolk!" Hagrid said something in the oily sounding language, then bowed to the merman.
Somewhat mollified, the being gave Megumin one last glare, then dove beneath the surface.
Hagrid kept watch, ensuring that more mundane methods of tadpole removal were employed for the rest of the detention, though he did call the tadpoles "cute little blighters."
That was the only major explosion before the feast, for which Megumin had developed a Cunning Plan.
"Everyone is going to be distracted by the Halloween Feast," Megumin told her compatriots. "Which means that this is the perfect time for us to infiltrate the Third Floor Dungeon!"
"Won't everyone notice that we've run off?" Darkness demanded.
"Ah, but this is where my ingenious plan comes into play!" Megumin cackled. "I shall pretend to gorge myself upon the food, and take ill! Thus, my companions will be required to escort me back to the tower, whereupon we shall go and plunder the treasure!"
"W-what about me?" Yunyun asked. "I-I can't go to the Gryffindor dorms."
"You shall simply need to pretend to contract an illness and go to the lavatory," Megumin said with a shrug. "Then, you shall break off and meet us at the dungeon entrance."
"Oh, um, o-ok," Yunyun agreed.
Ron was not particularly enthused about missing the Halloween Feat, until he had an idea. "I suppose I could gorge myself too and stagger off with you. Maybe smuggle in some extra supplies so we can eat while we do the dungeon crawl."
"Yes! I am glad you are finally thinking ahead. It is important for sidekicks to bring along extra supplies for when the party faces danger," Megumin agreed.
"Just try not to lose your wand again between now and Halloween," Hermione sighed. "You've had it for a week now and that's the longest you've ever gone. I'm surprised Hagrid didn't take it when you tried to blow up the lake."
"I was only trying to blow up the tadpoles. If I had wanted to blow up the lake, I would have succeeded," Megumin sniffed.
Meanwhile, a similar conversation was taking place in the Slytherin dorms.
"-so that's the plan," Kazuma was saying. "We'll use the laxative on ourselves, then run off to the loo. After that, we dose the toad and-"
"Isn't it a frog?" Dust asked.
"That's not important. What is important is that you follow the plan," Kazuma ordered.
"We're sure to run into Potter on the way, she'll have a mad scheme of her own cooked up," Draco pointed out.
"That's why we set the booby traps on the door beforehand!" Kazuma said, smacking Draco upside the back of his head and earning a glare from the other boy. "The grease trap and the binding trap are sure fire ways to make sure this goes off without a hitch!"
Thus, the night of the feast came, and both sets of adventurers embarked on their plans. Yunyun excused herself to the washroom, but none of the other students at the Hufflepuff table really noticed. Yunyun rarely talked to her housemates, and spent all of her free time hanging out with Megumin. The Hufflepuffs were good sorts, but they did think Yunyun was odd and wondered why she was even in their house.
Then the three Slytherin boys all pretended to take ill, at roughly the same time that Megumin and Ron made themselves actually ill, much to Percy's disgust.
"I thought mum told you to be a good influence on Megumin!" Percy said, hauling a groaning Ron out of his bench. "This is ridiculous! Behave yourself."
"Too...too much...urp...pumpkin...pasty," Ron moaned.
"We'll take care of him, Percy," Darkness promised, picking up both Ron and Megumin and slinging them over her shoulders. "We should have paid closer attention."
A few moments after the carnival of calamity had departed, Quirrell ran up and shouted, "TROLLLLL IN THE DUNGEON!"
He looked up with a pleading expression at the headmaster, then passed out.
Bedlam then erupted, but not for the reasons that Quirrell would have liked.
A few minutes earlier, Yunyun had been in the girl's lavatory, looking in the mirror.
"She sells sea shells by t-the s-sea...She sells she seals...She sells…" Yunyun sighed and rubbed at her face, then tried another tongue twister like her speech therapist had taught her. "Peter Piper picked a pickle of…"
Just then, Yunyun heard screams across the hall. She turned the water off and hurried outside to find the door to the boys lavatory had been knocked down.
"AAHHHHH! GET AWAY, GET AWAY!" Draco was shrieking, sounding for all the world like a panicked little girl.
"HAVE AT THEE, VILLAIN!" Dust's voice bellowed.
Kazuma, not being a fool, was trying to hush the other two and get them to hide, to little success.
"Ah! I'll help you, I'll help you!" Yunyun gasped, and hurried inside. What she found was a great grey troll, club raised, glaring down at the three Slytherin boys. Dust had picked up a mop and was jabbing at the troll, while Draco was cowering under a sink.
"Oh for the love of- You're Wizards!" Kazuma snapped, and pointed his wand at the troll. "Flipendo!"
The minor jinx barely even staggered the troll, but it redirected its blow at Kazuma who rolled away. "Ha! Nice try, fat-arse!"
Then the troll kicked Kazuma right in the arse, and sent him flying through the air. He ended up sitting in a urinal, much to his disgust.
Yunyun, however, was not one to stand by idly while danger reared its ugly head. "YOU! DON'T YOU DARE HURT MY FRIENDS!"
"Urgh?" The troll turned towards Yunyun, blinking down at the tiny girl. She was even smaller than the three boys, and the troll barely considered her to be worth a meal. "Urgh."
"I'm only going to ask this nicely once," Yunyun spat, pointing her wand at the troll's face. "Do you want to be my friend?"
"Fwen?" the troll growled.
Yunyun nodded happily. "Yes, fr-"
Then the troll tried to smash Yunyun with its club.
"Protego!"
The club skittered off the shield and smashed into the wall.
"URGH!" The troll raged, and tried to bat Yunyun aside with a fist.
She was not done however, and pointed her wand at the troll's club. "Sectumsempra!"
The troll's club was sliced cleanly at the haft, falling to the floor with a thud.
"Ha! Take this!" Dust cried, and expertly jabbed the troll in the back of the kneecap. The beast stumbled, trying to spin and attack this new threat, only for Dust to roll out of the way.
"YOU SON OF A BITCH, THAT WAS A NEW ROBE!" Kazuma raged, and pointed his wand at the off balance troll. "FLIPENDO MAXIMA!"
This time the spell hit the troll hard enough to send it crashing down, right in the direction of Yunyun.
For some reason, later he would claim he thought the troll was going to fall on him, Draco jumped forward, knocking Yunyun out of the way of the falling beast. He crouched over her, both of their eyes wide as Yunyun looked up at him.
"You were in my way," Draco said after a few heart beats, swallowing and getting up. "Stupid troll. How did it even-"
"URRRRRGHHH!"
The troll raged up, one hand batting Dust and his jabbing mop into a bathroom stall, the other knocking Kazuma sprawling. It sprang towards Yunyun and Draco, slobber flying everywhere from its open maw.
"CONFRINGO!" Yunyun roared.
The blast only caught the troll a glancing blow, but it was enough to knock every single one of the troll's rotten and crooked teeth right out of its mouth. It fell down with a crunch, dazed and bloodied. The four students were shell shocked as well, the minor explosion having deafened and blinded them.
Yunyun was the first to recover, staggering up, then helping first Draco to his feet, then Kazuma and Dust. Then she hobbled over to the troll, glaring down at it, her red eyes glowing through the falling bits of plaster in the air. When the troll blinked, its eyes crossed as it looked at the wand pointed right in its face.
"This is the last time I'm going to ask you," Yunyun said, her tone calm and even, but her red eyes blazing with deadly intent. "Do you want to be my friend?"
This time, the troll nodded frantically. "Fwen! Fwen!"
"Good," Yunyun said, nodding and lowering her wand.
"You want to be friends with a troll!?" Draco demanded incredulously.
Yunyun smiled sweetly at him. "Well, I'm friends with you, aren't I? Come on, friends! Let's go back to the feast."
And so it was that not ten seconds after Quirrell sprawled on the floor after raving about a troll in the dungeons, that Yunyun led the giant monster into the great hall by the hand, the Three Stooges trailing along with her.
"Um," Yunyun said, gaze darting around the terrified and frantically shouting inhabitants. "Um…"
With a sigh, Kazuma raised his wand and let loose a loud bang, which caused most everyone to freeze and look on in horror.
"Yo," Kazuma said. He jerked a thumb over his shoulder at the troll. "This is Yunyun's new friend."
"We named him Smiley!" Dust added brightly.
The big brute gave an encouraging grin, showing off his empty gums.
"H-he's my f-friend, now," Yunyun agreed.
"Young Miss Dursley," Dumbledore said slowly, "Do you mean to tell me that you befriended a troll that was loose in the dungeons?"
"Y-yes?" Yunyun stammered.
"Not before we beat it," Draco said, folding his arms over his chest.
"W-well, um, Smiley didn't w-want to be friends at f-first," Yunyun admitted. Then she looked up at the monster who's hand she was holding. "B-but now he wants to be friends, right?"
Dumb as trolls are, Smiley was very certain of one thing: He absolutely, positively, definitely, wanted to be the friend of this little demon that had so thoroughly trounced him. He nodded once more and said the only word he seemed to know: "Fwen! Fwen!"
"Fifty points to Hufflepuff," Dumbledore said, sinking back in his seat, a look of pure shock on his face.
"Um. D-Draco did s-save me too," Yunyun pointed out. "A-and Dust d-distracted the troll. And, um, Kazuma h-helped too."
"That is...very honest of you," Dumbledore managed. "Ten points each to Slytherin."
For his part, Quirrell could only grind his teeth. Foiled again, and by these same damnable children.
Meanwhile, Megumin, Darkness, Hermione, and Ron all raced for the door of the Third Floor Corridor.
"What about Yunyun?" Darkness panted when they arrived.
"No time!" Megumin declared. "We have to move quickly, or people will notice!"
"Just bloody well hold on, what about the frog?" Ron gasped.
"A small explosion will be enough to deal with it," Megumin decided, and reached for the door.
"Hold on, that's not a-" Hermione began, but then Megumin twisted the doorknob, and a few things happened.
First, the handle turned out to be a false one, and sprang away from the door. A shower of grease coated the four Gryffindors, causing them to all lose their footing and fall to the ground. Then, out of the door, several ropes sprang, which wrapped themselves tightly around each of the four students, binding them in place.
So five minutes later when Snape arrived, gasping and out of breath, he found his quarry already immobilized.
"What, exactly, are you idiots doing?" Snape growled.
"We have been attacked!" Megumin cried. "There were three kobolds, who used their trap making skills to-"
"I think not," Snape said, sneering at them. He freed them, keeping well back. "It seems you have not learned your lesson. Now. I am escorting the four of you to Gryffindor tower, where you will get cleaned up and remain until morning."
"But what about the feast?" Ron asked, giving Snape pleading looks.
"You made enough of a pig of yourself already, Weasley. Two points from Gryffindor each. Now get moving," Snape ordered.
Once Megumin's group had moved, Snape bent and studied the ropes. His eyes narrowed, and he peered into the false hole. Somehow, he knew.
"Crabbe," Snape spat. Well. It was time to put the headmaster's plan into action then. This was getting entirely out of hand.