What most of Hogwarts learned first on that otherwise-unexceptionable day was that Professor McGonagall could sure scream loud.
Professor Flitwickās Charms 5th-year Charms class was close enough to catch the full effect, and the door had been left open besides; en masse the students recoiled with shock and a miscast Hiccuping Charm broke one of the windows (out which the entire flock of ravens they were practicing on escaped to the Forbidden Forest where they only had to worry about centaurs, rather than annoying young humans with wands).
Up in the Divination Tower, Sibyl Trelawny preened over her foresight to have warned her students of an unprecedented catastrophe likely to occur before the hour was out.
Out in Greenhouse Five, a NEWT-level Herbology class looked up in puzzlement, and most of them were subsequently bitten by the Venomous Tentaculae they were attempting to propagate. It does not do to ignore a Venomous Tentacula when youāre prodding at its intimate parts with a cotton ball held in tweezers, so the class was cancelled while two-thirds of the students headed for the infirmary and the rest of them headed into the castle because if they stayed with the Venomous Tentaculae theyād be outnumbered, and nobody wants that.
And down in the dungeons, Professor Snape turned away from comparing Lee Jordanās Pepper-Up Potion to spoiled cream at what sounded like a woman screaming from the entrance hall. As the scream continued, rising in pitch, he ordered the class to remain where they were and behave, sweeping out of the room just in time to miss Theodore Nott suddenly jumping up and yelping as though someone had put a crocodile heart down the back of his robes.
Fred Weasley stepped back from the unfortunate Slytherin, shared a smirk with his twin, and stuck his head out the door to make sure Snape had rounded the corner before leading the way out of the classroom.
Back in the Transfiguration classroom, about forty-five minutes ago, it had started innocently enough. Ron Weasley, possessed of a broken wand and a lurking suspicion that most of the familyās magical talent had been soaked up by his siblings before he was around to get any, had attempted to turn his pet rat, Scabbers, into a teacup.
Scabbers had not become a teacup.
Scabbers, blast his useless scraggly little backside, had become a furry, vaguely teacup-shaped monstrosity out of which absolutely no one would have been tempted to drink, and to make matters worse, he still had a tail.
Harry was hiding a smile behind his hand. Dean and Seamus werenāt even trying to hide theirs, elbowing each other and laughing. Parvati and Lavender were looking with disgust and horror at either Scabbers or him, and Hermione was opening her mouth, no doubt ready to tell himĀ exactly what heād done wrong.
Which only made it worse that he really thought heād done everything right this time.
He snatched Scabbers off the desk (eww, the base of the cup had the same texture as rat feet) and turned away from Hermione. He made the wand movement again, picturing in his mind the way McGonagall had demonstrated it. āErreverto.ā
āErreverto. Erreverto.Ā Erreverto.ā
It didnāt work. It didnāt work when Professor McGonagall stopped by and gave Hermione two points for Gryffindor for getting the spell perfect in both directions. It didnāt work when Harry made his successful transfiguration (Ron looked; the pattern was a little bit furry but it was definitely a teacup). Ronās lips formed the shape of a word that wouldāve made his mother box his ears had she heard it and attempted the reverse transfiguration, which didnāt work either.
Finally, faced not only with the indignity of failure but the threat of Scabbers being stuck like that, heād gone up to Professor McGonagallās desk.
Professor McGonagall looked up from the paper she was grading and looked from him to the squirming teacup. āProblems, Mr. Weasley?ā
āUm, yeah, Professor. I canāt get it to work in either direction and itās not fair to Scabbers to make him stay as a teacup just because I canāt do a spell right and can you maybe ⦠?ā
āI suppose so, Mr. Weasley,ā she said, and waved her wand in theĀ exact manner Ron had been doing all along.
Professor McGonagall looked very, very puzzled.
āNow thatās odd,ā she said softly.
As one, the other students looked up; a few of them rose from their seats and quietly moved closer.
She did not attempt the transfiguration in the other direction. Instead, she made a complex motion with her wand and murmured an incantation that possibly only Hermione recognized. The teacup squeaked. Professor McGonagall looked more puzzled than ever, and made a sweeping wand movement that ended with a sharp jab and uttered, āArcanumĀ finite!ā
And there was a loud bang, and there was a pale, pudgy, and very naked man sprawled out on her desk, and she jumped back hard enough to knock her chair into the wall andĀ screamed.
Having taught a particularly rigorous course of magical study to children and teens for quite some time now, Minerva McGonagall had become accustomed to certain things. Students who didnāt listen. Students who did rude things to the mice when they thought she wasnāt looking. Students who accidentally turned a frog or a raven into a flock of starlings or a school of strange slimy South American fish (and tried to solve the immediate problem by filling the classroom with two feet of water, neglecting to consider the gap under the door). Students who tried to transfigure their noses into a more appealing shape and wound up in the hospital wing regrowing their nostrils.
Naked men on her desk was something Minerva McGonagall had never had an occasion to get used to. What made it worse was that she recognized this one, and heād been dead for more than a decade.
Inferius!Ā ws her first thought, followed shortly thereafter byĀ Animagus,Ā which collided withĀ Peter Pettigrew!Ā and produced the utterly horrifying thought ofĀ what if all four of them were Animagi? which didnāt bear thinking about at all, so her brain jumped toĀ if he wasnāt killed by a Dark Wizard then why didnāt he say so?Ā and realized there was only one possible explanation why, and about that time her eyes registered that parts of Peter Pettigrew she really doesnāt want to know about were flopping about in front of her face, and she was screaming as she jumped back.
The flow of invective which followed somehow failed to astonish her one bit. Some part of her registered, peripherally, the shocked faces of her students, but most of her attention was directed at Peter Pettigrew, who at very least faked his own death and at worst framed Sirius Black andĀ if Black didnāt betray the Potters then who ⦠did.Ā And the words poured out of her, filthy English and filthier Latin while Pettigrew squirmed on the table, his face rage and guilt and fear and something shifty and contemptible, and he turned to look at the stunned students, calculating, and then lunged for Ron Weasleyās wand.
Severus Snape had reached the Entrance Hall by the time the scream died away and the invective replaced it. He almost smirked, amid the alarm; of all the things heād never expected to hear from Minerva McGonagall ⦠he took the stairs two at a time, still not noticing the students who followed.
He did notice the Herbology class, which had stopped on the way to the Infirmary and were staring transfixed in the direction of the Transfiguration classroom, but pushed his way through them, getting Venomous Tentacula pollen all over his robes in the process.
From the other end of the corridor came Professor Flitwickās Charms class, with Professor Flitwick bringing up the rear and pushing his way between students.
Ron looked stunned as the man whoād been his pet rat snatched the wand from his hand; Professor McGonagalās expression shifted to one beyond fury and when the entire class recoiled, it wasnāt from the naked man with the wand.
āLaedo!ā Minerva McGonagall snapped.
Ron Weasleyās wand cast a Splintering Curse many years beyond its rightful ownerās abilities, and it did Peter Pettigrew the poor favor of eliminating the door, which might have slowed him down a bit.
Severus Snape flailed and skidded to a halt as the Transfiguration classroomās door shattered. He stepped back just in time, and stared, jaw dropped in shock, as a naked man he recognized from his school days flew past him and bellyflopped against the wall, bounced, and collapsed to the ground just in time to avoid the āExitium!ā which followed and vaporized an impresive chunk of the castleās stone wall.
Fred and George and Lee Jordan, determined to stay at the front of the crowd, had been pushed almost against Professor Snape by their fellow Potions classmates and some pollen-coated Hufflepuffs. Fred squirmed aside hastily as Professor McGonagall appeared in the doorway, the look on her face so utterly livid that Professors Snape and Flitwick both reflexively stepped back.
Snape tripped over Georgeās foot and fell against a knot of Hufflepuffs, releasing another cloud of pollen and knocking them backwards. Pettigrew saw his opportunity and took it, scrambling to his feet, stumbling sideways, and launching himself towards the gap.
And Minerva McGonagall made a thrust with her wand and said, āPerdo.ā
In the very loud silence which followed, Filius Flitwick squeaked, āThe Splinching Charm, Minerva?ā
She mightāve looked embarrassed for a moment, and then she smiled as she looked down at Pettigrew, who lay on his belly, his arms and legs lying akimbo some distance away.
āUnorthodox,ā she said, ābut useful in a pinch. If someone would inform the Headmaster, and send an owl to the Ministryānot Fudge, not Crouch, someone competentāShacklebolt, perhaps. Students, return to your classrooms, please. Mr. Weasley, Iām very sorry, but I do believe itās impossible to return you your rat. However, the zero I was going to have to give you for the dayās work is entirely undeserved, as you were not transfiguring a normal rat. You may make the lesson up any time this week.ā
The story was, of course, much embellished by the time it reached all the students. Versions of it had the intruder peppering Snape with a Glitter Hex or transfiguring Ronās rat into a pair of boxers, and people had to be disabused of the notion that it had been Voldemort whoād been hiding as a rat all this time.
Snape gave both Weasley twins detention for tripping him, and took forty-seven points total from Gryffindor over the next few weeks for various and sundry pollen references.
Kingsley Shacklebolt showed up with a team of Aurors in time to meet Professor Dumbledore; the Wizengamot launched an investigation into the events surrounding the Pottersā murder; the results turned into a scandal which saw the release of Sirius Black and the forced resignation of both Director Bartemious Crouch and Minister Cornelius Fudge. Director of Magical Law Enforcement Amelia Bones was confirmed as Minister of Magic shortly thereafte, and the Daily Prophet reported that Sirius Black (āGodfather to the Boy-Who-Lived!ā āFramed, Abandoned, Condemned to Living Hell!ā āHeart-Wrenching: His Release In Pictures, Page 17!ā) was considering applying for a teaching position at Hogwarts, ābut just for a year, Iāve been cursed enough for one lifetime.ā (āTheĀ Prophet reminds its readers that the so-called "curseā on a certain Hogwarts teaching position is almost certainly a mere string of coincidences.ā)
And, Minerva thought with relish some months later, it was almost seven weeks before anyone attempted messing around in her class.