The tickle cell.

"Here's how it works," said the Depantor, gesturing with its tentacles. "You see that mirrored wall?"

"Yes," muttered Hermione. She could see the mirrored wall very clearly. She could also see herself, reflected in it. She was fastened into a harness of leather straps, hanging from the ceiling of the cell, arms bound behindher back, legs spread so her pussy was completely exposed. Stark naked, of course. The Depantor gave her a little nudge with a tentacle and she swung gently from side to side.

"On the other side of that wall," it said, "is a whole class full of Slytherins. They can't see you right now. But if I move the wall, they'll be able to. Would you like me to move the wall, Hermione?"

"...no."

"Why not?"

"... because I'm naked."

"And it'd be pretty embarrassing for a bunch of Slytherins to see you naked, wouldn't it?"

"...yes."

"And they've all got cameras. Wouldn't it be even worse if all the Slytherins took pictures of you? Bet you want that wall to stay where it is, don't you?"

"...yes."

"That's great," said the Depantor. "Unluckily for you, I'm an evil monster from another dimension that loves to make pretty girls like you squirm and suffer. But I'm going to give you a chance. See, Hermione, if you make a single sound, that wall is going to disappear. Do you like the sound of that?"

"..."

"Staying silent. Clever. Now, what I'm going to do is tickle you." From out of nowhere the Depantor produced half a dozen long, white, soft feathers. "The instant you squeal or giggle or respond in any way at all, goodbye to the wall, and all the Slytherins will get to watch. If you hold out for half an hour, I might be nice and let you go. But you won't. Are you ready?"

"...!"

"Excellent. Let's go."

There was a long pause, and then Hermione felt a soft feather began to gently trace figure eights across the small of her back. At first it felt nice. Then, it felt maddening. It just kept going, rotating around and around, sending goosebumps prickle across her body and making her bite her lip to keep from yelping. She didn't know why it was so intolerable. It just was.

She hated being tickled. She hated it so Merlin-blasted much.

A second feather began to tease her ribs. She had thought the first one was annoying, but this one was ten times worse. It flitted gently, frustratingly, up and down her sides, making her squirm in her bonds as she struggled desperately to pull away from it. She could feel a giggle building in her throat. She bit down on it. She couldn't let the Slytherins see her without any clothes on, and laugh, and take pictures. She had to hold on.

A third feather danced across her nipples.

A squeak almost escaped Hermione's lips. She caught it just in time. She glanced at herself in the mirror and saw with a rush of shame that she looked completely ridiculous. Her cheeks were flaming red and she wore an expression of adorable, absurd frustration as she writhed in her bonds, gritting her teeth and trying to struggle away from the feather that crept back towards her small breasts. Her rosebud nipples stiffened as it tantalised them, tracing circles around her areola.

It wasn't fair! They couldn't do this! How was it allowed? The worst part was, it actually almost felt good, and somehow that made it even more embarrassing.

A fourth feather found its way under her knee. A fifth tucked itself into her armpit. A sixth began to scrape across the soles of her bare feet, prodding and poking and seeking out her most sensitive spots. That one almost got her, but she screwed up all her courage and clamped down on the chuckle, keeping it locked up inside as the Depantor calmly and patiently investigated every **** place on her body.

She blushed brightly as she rocked back and forth, silently squirming, seeing herself in the mirror, intensely aware of how silly she looked. There were dozens of Slytherins just on the other side of that wall, waiting patiently for her to slip up. She couldn't give them the satisfaction. She couldn't let all those bloody Slytherins have the pleasure of seeing Hermione Granger brought low, small and stupid and stark naked and begging pathetically for mercy as she was tickle-tortured to within an inch of her life. Just thinking about it made her furious. It wasn't acceptable. She had to hold on, even if...

A feather flicked across her pussy.

"You like that, huh?" said the Depantor, as Hermione's lips parted. She shook her head in silent desparation as it slid across her labia, teasing her womanhood mercilessly. Oh, god, she was so sensitive down there. So unbearably ticklish, and it was moving slowly and carefully up to the most private part of her body. When it touched her clit...

She was going to break. She was going to moan, and giggle, and squeal, and the wall would come down, and all the Slytherins would see her moaning and giggling and squealing. With no clothes on. And they'd all laugh. And she'd have to hang there, stark naked, looking utterly foolish, while all her worst enemies laughed and cheered and applauded and made fun of her and took pictures to remember it forever. She'd never live it down. And it was going to happen. Because she knew now, as the feather slowly crept towards her clit, that she couldn't stop it. Her whole body tingled in anticipation. Her heart was pounding. She really, really, really, really wished this wasn't happening. But it was. There was no way out. And any second now...

The feather flicked across her clit.

"EEEEEEEEEK! EEEEK EEEEK EEEEEEEK EEEEEEEEEK! STOP! STOP STOP STOOOOOOP! AHAHAHAHAHAHAHAAAAA!"