"NYAAAAAAAAAAAAAAAAAAA!" Voldemort cried, releasing a shockwave of magic that blasted all the windows and occupants of the Great Hall.
And then he did it. Commited the worst crime of all.
"So." Voldemort hissed. "Hogwarts has lowered itself to harbour Squibs. Those unworthy of magic."
Argus Filch stood, frozen with fear as Voldemort advanced on him; students, current and former, whom he'd tormented, tried to come to his aid, but Voldemort's Death Eaters blocked their way.
"You want a taste of Magic, Squib?" Voldemort asked, relish in his voice. "I…oblige. CRUCIO!"
Filch fell to the floor, screaming in agony – but suddenly, out of nowhere apparent, came his salvation.
It wasn't Harry Potter! It wasn't even the Temporal Ghost of Albus Dumbledore…it was…gloriously coloured, a rainbow trail blazing through the air "Nyannyannyannyannyannyannyan nyannyannyannyannyannyannyan nyannyan" It was…Nyan Mrs Norris!
Mrs Norris swooped down, clawing at Voldemort's eyes. Voldemort screeched: "NYAAAA!" And Mrs Norris, yowling, went flying, landed on her feet, and then bounded at Voldemort.
"FOR CATS!" Minerva McGonagall and Ginevra Weasley roared, charging at Voldemort, lead by the feline warrior herself – no Death Eater could stand before them, as all three clawed through Voldemort's warriors, until they came at last to the evil man himself.
Ginny and McGonagall did not fight Voldemort – that was not their role. They stopped his Death Eaters coming to his aid.
"For Felinia!" Crookshanks cried the battle-call of his species, landing next to Mrs Norris.
"Avada Kedavra!" Voldemort, feeling quite foolish duelling a pair of cats, enunciated. Mrs Norris blasted him with a rainbow and he didn't get up.
The celebrations lasted well into the next night. Argus Filch walked Mrs Norris down Cat Aisle and a transformed Professor McGonagall acted as bridesmaid at the heroes' wedding, an event watched by all Wizardkind.