Disclaimer: I don't own the things owned by J.K. Rowling or whoever else has the rights to the Harry Potter franchise/series/books/whatever. This was not made for money making purposes, but for the enjoyemnt of fans and others.
Voldemort's Secret Weapon
His opponent was very knowledgeable in the many branches of magic. His opponent spoke many languages and so knew a plethora of spells that would take a split second or more to figure out the effects of, precious seconds that could determine the outcome of their battle.
He needed an ace of his own, he wasn't as old as the old man, he was several decades the man's younger after all. He needed his own trump card, something that would surely throw off his foe, and at the same time add to his reputation, not only as a skilled wizard, but a terrifying creature.
He was going for crazy.
While he could use parseltongue for his spells, that just had a creepy factor, not an insane factor. He needed something new, something fresh, something that not even his opponent would use. He needed an ancient language, a black art, something unique.
It was as he was torturing a muggle family to insanity that he came upon a brilliant idea, it was so stupendous that he blew up the house that the muggle family he was torturing had called home in his excitement. This was followed up by beheading the family members just before they went insane in his glee.
He had been visibly smiling as he did it, his followers, his servants, were even more frightened of him as he did so. He had done the deeds without even looking in the direction of where his spells had flown and they had hit their targets perfectly.
He refrained from skipping as he moved toward the aurors that had arrived and swiftly erected anti-apparation and anti-portkey wards around the area to try and detain him and his followers, to try and stall them until reinforcements could arrive and try, but would still fail, to take him and his followers out or have them down for the count.
It was a bold strategy, but one that was not well thought of. They hadn't counted on him finding them so quickly and sending them to their next great adventures so swiftly as well.
His followers knew that something was definitely up, knew that there was some change in their lord and master, that he had something new up his sleeve, a recent discovery or something similar. Possibly something that their enemy wouldn't expect, a new spell perhaps or power ritual.
They watched as cut down the aurors, he didn't use one of his two favorite spells to do it, he used a curse that sliced and diced the aurors. A swift, yet painful, death that served to add a little bit more fear into the hearts of the remaining aurors.
The aurors of course did not flee, but at the same time they did not put up much of a fight. Only one made it out of the battle alive, she'd accidentally set off her own emergency portkey, and so managed to brief her superiors on the situation, a situation that they were too late to get a better outcome since as soon as they arrived the battle was already over and all that was left of their forces on the ground were their corpses, courtesy of, not a zealous, but giddy Dark Lord.
It was some time later, after his discovery, that he finally managed to translate a large number of his spells to the language that he had decided to use in his next fight. It was easy enough to do, he just had to remember to follow the simple rules that the language had.
He was quite certain that a vast majority of the pureblood population wouldn't be able to recognize it, and thus tried his hand at trying to speak the language, speak as in conversation style speaking and not merely using the language for incantations.
It sounded so odd, even to his ears. He was certain that he could outwit the old man, even for but a while.
With newfound confidence in his own abilities, he dared to plan and implement said plan on a Hogsmeade weekend. There were sure to be a lot of witnesses there.
Before he set out to do battle with one of the most powerful and respected wizards of the age, he practiced his weapon a little bit more, he could not afford to make a mistake. He also practiced his Cruciatus Curse on a few prisoners that were still alive, a bunch of muggles that understood what he had been saying to them and so laughed because they never thought that they'd find an evil bastard such as he.
It was the laughter of the insane, sweet music to his ears.
When he was done with that he began his attack, it was to be the most brutal and deadly out of all the attacks during the war. The body count would be so great, that Hogsmeade weekends would be cancelled until such a time that the war was finally declared as over.
His forces knew what they had to do, kill as many halfbloods and muggleborns as they could find. They were all very aware of just who among the students were purebloods, being mostly purebloods themselves. They were also aware of just who among the populace were of such stock, and so would only torture and kill purebloods that stood against them. But in the end it did not matter, all that mattered was the chaos that was sown.
He popped into the quaint village with nary a sonic boom that sent civilians flying to the ground, landing in heaps, before their screams drowned out any groans that might want to leave their lips.
All over the village were the musical notes and tones of screams and shouts and the sounds of fighting.
He flung fireballs at the houses and shops, all manner of light to the darkest of the dark arts' curses that he knew at any that dared to cross his path, even the puppy that tried barking at him. He didn't put that pup down, he did not disappoint in how evil he was, he physically kicked it before forcing it to go hunt down its master and chew said master to death, unles its master was already dead.
He flung curses, left, right, up, down, and center, in the very heart of the village as he waited for the arrival of his greatest foe, the Light Lord, though he never called himself that, Albus Dumbledore. The one man that all knew, could send him running or at the very least calling for a retreat. The one man that had such an obsession with candies that it was a wonder that the old man still had a complete set of ALL of his teeth, and they were all pearly white too.
The old man finally did arrive, by phoenix fire too. It was a splendid show of power, of force, of dramatics.
The old man arrived in classic hero fashion, and tried to engage him in small talk, get him talking, and so he obliged the old man's request. He monologued, but not enough for the old man to get a stunner in.
"Inallyfay ecidedday otay acegray usway ithway ouryay esencepray, avehay ouyay? I'veway eenbay illingkay otnay onlyway imetay aitingway orfay ouyay otay arriveway, utbay away otlay ofway ouryay eciouspray udentsstay ootay," Voldemort calmly stated, "Ouyay on'tday owknay atwhay I'mway ayingsay, oday ouyay?"
That short speech really was something that had caused the old man's mind to temporarily shut down due to shortcircuiting. But it wasn't enough to kill off his instincts and reflexes as he dodged the killing curse sent his way.
"Avadaway Edavrakay!" Voldemort had incanted.
He was aware that words and wand movements weren't really all that important when casting, they were merely tools to help focus one's mind and one's magic on the desired outcome, not that many magicals were aware of that fact.
A shield was raised, and the old man could do nothing more than dodge out of the way of the spells that were fired in his direction with near perfect precision.
They cut through the air like knives through butter and it was only his war honed reflexes and survival instincts that were saving him from a lot of pain and certain death.
"Esticletay Emovalray!" Voldemort shouted out, he knew that words were meaningless after all and didn't want to butcher his bastardized Latin any further than he had already done.
Using relatively normal wordings made the visualization or intention all the more clear when he cast his magic in the direction of the old man. Even the color of the arrowheaded bolt of light could be controlled.
"Utnay Ackercray!" he was really enjoying the continued look of confusion on the old man's face, and the continued lowering of morale of the forces of all that was good and decent in the world, as far as their definition or perception of themselves went at least.
Shields were shattered, bricks were broken, but the old man just kept leaping out of the way of the brightly colored lights. His wand was also used to misdirect or redirect or even deflect some of the spells sent his way.
"Urntay Intoway Away Iantgay Ausagesay!" Voldemort rapidly incanted as he swished his wand in a dramatic fashion, making those watching the fight believe that it was some kind of really dark spell.
The old man was quick to summon a brick to intercept the sickly purple spell, and to his great surprise it turned into a massive red and oily thing. He didn't know what it was, but it surely couldn't be good for his health. He'd failed to notice that it was a really odd transfiguration.
"Anceday Ausagesay, Anceday!" Voldemort shouted as he pointed his wand at the massive piece of meat, and it did bounce around and did some additional property damage until someone managed to bring it down, at the end of the battle, but that was much later.
The old man believed that the spell was meant to turn him into a monster that the dark lord could control to further bring about more deaths.
He tried to get back his resolve and fight back, but before he even could, another spell was fired in his direction, spells were fired in rapid succession, not really giving him much time to bring his wand up to do more and defend himself.
"Isttway Ishay Armway!" the dark lord shouted and the spell barely missed the old man's arm, it shattered the wall that the old man had been standing in front of, due mostly to the power behind the spell than the spell's actual effect.
"Urntay Intoway Away Eletubbytay!" that was one spell that had three more monsters take the field, they were these demonic creatures with moving pictures on their bellies and came in four different colors. The magical world had never seen them before, and Voldemort had only seen them on a drawing pinned to a corkboard in one of the homes of the muggles he had placed under his tender loving care.
"Aymay Ethay Orcefay Ebay Ithway Ouyay!" was a bastardized banishing charm, altered in that a wand wasn't used to cast it, but a palm thrust was used, it actually did connect and did manage to shove the headmaster into a bunch of aurors that were killed a moment after helping the old man to his feet.
They were the perfect meatshields, though Voldemort supposed that the old man hadn't intended them to take the hit for him.
"Illspay Ouryay Utsgay!" was a spell that missed the old man as he jumped up as a spell impacted with the ground that he was standing on. It had the effect of disemboweling the Gryffindor student that had been dueling with a Death Eater a few meters away from the two battling lords.
"Apsnay Ouryay Inespay!" the spell was a combination of powerful compulsion and imperius curse, for some reason it richocheted off of the pipe that the headmaster had put in its path, and slammed into a seventh year Hufflepuff. It did not send the student flying, it did not do anything other than cause the student to bend herself backwards until her spine snapped.
Voldemort had been dancing within a general area as he fired of spell after spell after spell at his own trasfiguration professor. He was having the time of his life, while the headmaster was suffering a rather humiliating experience.
While Voldemort didn't mind fighting the way he was, more and more reinforcements were arriving and he noticed that his forces were growing tired. Perhaps it was time for a last spell, some final taunts, before he called for a retreat, it would be a win in his favor after all, what with all the death and destruction that had been dealt with.
He stopped casting curses and charms at his opponent, an opponent that was only physically exhausted as he had not expended a lot of magic during his run, jump, shield, block, deflect, dodge, part of the fight.
"What's wrong my boy? Tired? All that dark magic must have really cost you a lot of power," the old man tried taunting, unaware of the fact that not all of the spells were dark magic, in fact only the ones that caused any real bodily harm were the dark ones, the rest were household stuff and transfigurations.
To further mock the dark lord, the headmaster pulled out a lemon drop and sucked on it a bit before popping it and another one into his mouth, visibly showing that he was experiencing a momentary bliss.
"Iway amway otnay ouryay oybay! Ogay angbay away oatgay ikelay atthay assway immingray otherbray ofway oursyay, ouyay ecrepitday oldway oatgay!" was Voldemort's response to that taunt, he was pissed off enough not to notice that he hadn't spoken in English at all, he was that into his secret weapon.
"I'm sorry, was that supposed to do something? Maybe you should stick to a cheering charm, at your present level of power, maybe that would work," the old man suggested mockingly.
"Eeringchay armchay? Ouyay AREDAY ockmay ethay eatgray Ordlay Oldemortvay! Iway allshay efileday ouyay inway uchsay away ayway atthay ou'llyay evernay inkthay ofway ivinggay emay away econdsay ancechay everway againway!" Voldemort shouted in response.
He summoned a bag of lemon drops from Honeydukes, and enlarged them with a wave of his wand. He followed that up by animating them and applying an illusion that only he and the headmaster could see.
The enlarged lemon drops were pleading for their lives, for Dumbledore to save them from the evil Dark Lord.
That actually got the old man to somewhat choke on his lemon drops and for his mouth to hang open.
Onlookers believed it was the craziest thing for anyone to do. Mocking Dumbledore in such a way, was surely a last ditch effort at distraction. The Dark Lord must have well and truly snapped, more than he already had.
"Iway atehay emonlay opsdray! Ieday emonlay opsdray! Ieday!" Voldemort shouted as he hurled what appaered to be blasting hexes at the enlarged sour sweets, to Dumbledore it was like his best friends were dying and screaming or death wailing with him powerless to do anything.
When Voldemort was done, he signalled his forces to retreat, while he himself fired a last minute Killing Curse at the headmaster, who managed to block the unblockable with the one thing that apparently could be used to do so.
A Killing Curse of his own.
Onlookers could hardly believe their eyes, the great and powerful Albus Dumbledore had fired a killing curse at a killing curse. It was like how only a diamond could cut a diamond, or so the magical world thought of course.
Many aurors and old friends of the old man were aware that the old man could cast teh spell, they knew that he'd never use it on anyone, not even Voldemort. But they were equally surprised that he'd think of using such a dark and deadly spell as a way to defend himself.
Even Voldemort was a bit surprised by it, but not too surprised to splinch himself as he apparated back to his base. It was a job well done, a success, and he allowed his followers to celebrate their victory.
The evening edition of the Daily Prophet's headline read:
Dark Lord Murders Lemon Drops; Headmaster on the Warpath
The wizarding world took such headlines in stride, they were aware of course, that powerful people were oftentimes a bit barmy.
Dumbledore was left alone after the Hogsmeade Massacre as he had been found in his office banging his head against his beautiful mahogany desk with a muggle textbook laying on it.
The Dark Lord, Lord Voldemort, had made a fool out of him by using something that most purebloods would not recognize: Pig-Latin