This one is a bit different - a bit more fun. And a lighter tone for a theme usually associated with doom and gloom. Maybe my favourite so far. =)

Theme Four: Dark

A mischievous, unnamed third year took it upon himself to prank the sixth year prefects on the last day of classes. While some pranksters may have felt certain areas and situations were indisputably off-limits, and should never be tampered with, this particular trickster had no such scruples, and therefore decided the perfect place to attack was the prefects' bathroom on the fifth floor. A symbol, he was sure, of their status, with the added benefit of involving unmentionable bodily functions and occasional nudity.

The opening of Weasleys' Wizard Wheezes earlier that year afforded him a wide assortment of products to meet his every pranking need. Though all Weasley merchandise had been banned by Filch, and all in-coming mail was being monitored, Fred and George had devised methods for camouflaging packages so they could reach students' hands.

He was now in possession of several such items, including Cupid Crystals – a special order concoction which, unlike other WonderWitch potions that caused the drinker to become infatuated with the giver, caused the recipient to briefly experience all-consuming, passionate, grossly romantic impulses towards the first person they laid eyes on. His plan was to unleash the crystals in the prefect bathroom and enjoy the ensuing confusion and chaos.

He bided his time, waiting, watching, until late evening when a handful of prefects had entered the bathroom to get ready for bed: the redhead and his brunette friend from Gryffindor, the female prefect from Ravenclaw, and the two Slytherin prefects – the pug-faced gossip and that snob Malfoy. He sneaked quietly past the statue of Boris the Bewildered, to the fourth door, and whispered the password he had heard them use (that Slytherin girl had apparently never learned the art of whispering).

He stole a quick peek inside (wow, their bathroom was beautiful! A person could swim in that tub!). The three girls were at the sinks, brushing their teeth and doing whatever else it was girls did to get ready for bed. They were engaged in some kind of fierce argument about something that didn't interest him. He assumed the two guys were in the stalls, since he couldn't see either of them. He would have liked for at least one of them to have been in the tub – that would have been hilarious – but it was now or never.

The jokester pulled the cork off the bottle with his teeth, and lobbed it into the bathroom. It landed on the stone floor with a crash and shattered into a hundred pieces. The sudden noise startled everyone in the bathroom, and he quickly ducked his head out.

A substance resembling black fog instantly filled the room. But it had no density and soon plunged the bathroom into impenetrable darkness.

Pansy Parkinson screamed.

"It's Peruvian Instant Darkness Powder!" Ron yelled, recognizing his brothers' handiwork. He stumbled out of a stall and tried to feel his way towards the sinks, where he knew Hermione to be.

"We should wait until it wears off," she calmly suggested, "before someone gets hurt. Nobody move," she added, as Ron crashed into the side of the nearest sink and swore loudly.

"No way. C'mon. Let's get out of here." Ron reached out in the direction her voice had come and grabbed a thin wrist. With more swearing and stubbing of toes, Ron finally guided the girl to the door. It opened and closed behind the pair, but not even the dim light from the corridor could permeate the darkness.

"I hate the dark," Pansy wailed. An old childhood fear of hers that she had never completely shaken. She, like Ron, felt that she could not stand another minute in the pitch-black bathroom, and began to search for the door.

"There's nothing wrong with darkness," Draco drawled, gliding through the dark as easily as if it were the hallways of Malfoy Manor. Snakes do not rely on their sense of sight. The door opened again. There were only two prefects left in the bathroom. "Now, that we're alone," he murmured slyly, "let me show you how much fun the dark can be."

He seized the girl and kissed her. Led only by his sense of touch, he embraced her, ran his thin fingers over her waist, her hips. She returned the kiss with passion, and intensified it. She tasted like spearmint toothpaste and the feathered ends of quills.

As they snogged with great zeal, her hands were in his hair, clawing at his back, pulling him near. God, he thought, she's an amazing kisser. Why hasn't she ever kissed me like this before? The intensity of their embrace dulled his brain, and Draco barely registered that "Pansy" smelled better than usual. Like fresh laundered pyjamas, spring flowers, and coconut. And he didn't remember her hair being in a high ponytail when they had entered the bathroom. Her hair felt softer, less sleek – more bushy.

The darkness faded, but Draco didn't notice. His eyes were closed, and he was a little too busy to notice his surroundings.

"Well," the one word was stretched into two syllables. "What do we have here?" Draco knew that whiny, high-pitched voice. Myrtle. The girl in his arms pulled away from him. He reluctantly opened his eyes, and gave a start to see not Pansy but Hermione Granger in front of him, attempting to fix her hair back into a taut ponytail.

Draco gave a surprised cough. For once, he had no idea what to say. He couldn't even think of a smart-ass retort. He blinked several times, as though this would cause Hermione to morph into Pansy, and attempted to cover his speechlessness by straightening his robes.

Moaning Myrtle giggled. "My, my," she clucked, and disappeared through the nearest toilet.

"Well, Granger, that was –"

"Amazing?" she smirked at him expectantly.

"What? No. I've had, uh, well I think I've had..."

"Better?" Hermione's smile widened, and unexpectedly she leaned in and kissed him, leaving him confused and breathless. "Maybe we just need more practice. We'll have to do this again sometime." She retrieved her toothpaste and toothbrush, and gave him a small wave. "And not in a toilet."

With a swish of her long ponytail, Hermione left.

"Is it gone?" Ron asked, when she had emerged, Padma still at his side. She was both glowering and blushing - clearly she was still holding onto her Yule Ball grudge - and Ron's ears were a dark shade of red.

"Yes. I told you it was easier to wait. I wonder where it came from," she added thoughtfully. She glanced around the deserted corridor, but she did not see the perplexed prankster huddled behind a statue. "Come on. Let's go back to the common room."

The third year didn't know how he could have made such a mistake. Ron had barged out of the bathroom, dragging along Padma Patil, and yelling about Peruvians and cursing his brothers. This was not the love-fest he had been anticipating. Pansy had stumbled out shortly after, complaining about darkness and wondering how someone was supposed to pee when they couldn't see an inch in front of their face. He realized then he had grabbed the wrong bottle from his trunk. Both his Peruvian Instant Darkness and Cupid Crystals had been disguised as cough potions – he should have checked the labelling.

Draco finally emerged from the bathroom, looking dishevelled, and wearing an odd lopsided grin. "What happened?" Pansy demanded, inspecting him shrewdly.

"Peruvian Instant Darkness Powder. Best. Invention. Ever."