Disclaimer: See previous disclaimer...
Ultimately, it had all Peeves' fault. It hadn't been Peeves' fault that Ginny was bored and had wandered into Moaning Myrtle's lavatory where Harry, Hermione and Ron were working on their second Polyjuice potion. It hadn't been Peeves' fault that the twins were working on a potentially illegal potion for a new joke sweet. And it hadn't been Peeves' fault that Draco Malfoy just happened to be patrolling that corridor as part of his prefect duties on the night that things went completely wrong... And though he had no help in any of these things, it had still been Peeves' fault.
It had been perhaps ten minutes before curfew when Ginny had slipped into the girls lavatory. She knew that Hermione was once again brewing the Polyjuice for her best mates and, judging by the soft laughter when she first opened the door, the brewing was going well.
"I still can't believe you three have done this before. All the sneaking around to brew a potion here of all places." Ginny shook her head as she deposited a freshly nicked ingredient into Hermione's eager hands. "But then again, since you three have been doing nerve wracking things since your first year..."With a disbelieving shake of her head, Ginny seated herself near Harry as they watched Hermione work.
Ron clucked his tongue at Ginny in a patronizing manner. "At least this time we won't be turning into Crabbe, Goyle and Furball." Ron grinned at Hermione's disgruntled humph. "And using it to spy and get revenge on Umbridge is a lot more fun than trying to find the Heir of Slytherin."
Turning an emerald glance at Ginny, Harry smiled when she didn't so much as flinch at the mention of the incident in her first year. He gave a lazy half smile and remained silent as he watched not the potion being brewed, but the way the dim lighting seemed to play with the smoldering crimson strands of Ginny's hair.
Right about then, beyond the lavatory door and in the corridor, the infamous Weasley twins were working in the shadow of a suit of armor. Their latest prank was to spell the armor so that it would spit a bit of the potion currently stored within a flash in George's left hand out at random students during the course of the next day. They worked perfectly together, movements matched by years of practice as they murmured spells and prodded the suit experimentally.
A faint glimmer of light at one end of the hall caught Fred's attention and he nudged George, pointing down the hall to where Draco Malfoy could be seen just entering the corridor as he started rounds. His prefect partner was nowhere in sight and as such, the twins gave the same devious grin as they pulled further back into the shadows of the armor. George pulled the stopper from the potion flask and was just about to pour the potion into the suit when Peeves swooped down cackling.
"No fair having fun without me!" Peeves screeched as he snatched the flask from George's hand and flew further down the corridor and up out of reach.
"Peeves!" The anguished joint wail of the twins was almost comical as they burst from their hiding spot and ran toward the poltergeist.
With a mad hyena-like cackle, Peeves took off away from the twins. Perhaps he would have gone down the hall and ended up on the other side of the castle. Instead, Peeves spotted Draco Malfoy heading in their direction. One glance at the Slytherin crest on Malfoy's robes was all it took for Peeves to think of the Bloody Baron and turn into the nearest doorway.
"What do we have here!" Peeves demanded loudly, halting at the sight of the quartet of Gryffindors near the hovering ghost of Myrtle.
No one had a chance to even comprehend formulating an answer before Fred and George burst into the bathroom. They paused before giving slight nods and speaking in unison. "Well, well, well... What do we have here?"
"What we have here is a group of Gryffindorks that are about to lose a lot of points and the lead for the House Cup."
Everyone's attention was once more drawn to the door where Draco Malfoy leaned indolently against the frame. "I've already sent my patrol partner to fetch Professor Snape." He drawled, glancing negligently at his fingernails. "Perhaps he'll give you all a month or more of detention for this." He was bluffing of course, but they didn't need to know that!
Unfortunately, Draco's interference had drawn everyone's attention away from Peeves. That was never a good thing to happen. During the time it had taken Draco to make his little speech, Peeves had gleefully dumped the twins' potion into the brewing Polyjuice potion. The mixture was beginning to hiss and burble violently and drew Hermione's attention.
"Peeves! What have you done to our potion!" She screeched as Peeves snatched the cauldron from the stall, fumbling in her robes for her wand.
Peeves cackled madly as Moaning Myrtle emerged from her toilet. "I'm making sure we all have fun!" He shouted before dropping a rather nasty looking firework into the cauldron.
Not even Draco, as far away from the others as he was, could move fast enough to avoid the explosion as the firework detonated within the cauldron. The already volatile mixture of potions erupted, coating all seven students and the lavatory in its slimy mess as shards of the cauldron flew out. The shards sliced into Ron, Hermione, George and Ginny causing them to make various sounds of pain. That only lasted a full moment before all of them screamed as the effects of the mixed potions began to kick in.
"You've hurt Harry!" Myrtle was suddenly a violent demon of a ghost as she hurled herself at the poltergeist. Shoving Peeves through the floor as he shrieked with fear, Myrtle screeched for the Baron.
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The combined voices of seven students screaming in pain, one poltergeist screaming in fear, one ghost insanely wailing in fury woke up a good half of the castle. Professors ran toward the sound of the disturbance as others made sure the students in their dorms remained there. As it was, Professor Snape was the first one on the scene.
By the time he got there Harry, Hermione, Ron, Ginny, George, Fred and Draco were all unconscious and lying in a puddle of foul smelling brew. Almost absentmindedly he found himself pulling an empty vial from a pocket in his robe and filling it with a scraping of the potion from the bathroom walls and then he waited. With all seven unconscious, he would need assistance to move them out of the bathroom without anyone else getting the potion on them.
Hearing the sound of approaching footsteps moving at a run, Snape was about to turn around when a soft flutter from within the bathroom drew his attention. Turning his full attention to the students, Snape was more than a bit surprised to see a large golden wing stretching out from one of their backs...
Note: I finally got around to reading Prisoner of Azkaban. I can't read Goblet of Fire until after I see the movie though... It'll be 2008 before I get around to reading HBP!