Disclaimer: Harry Potter and Pokemon belong to their respective owners, and I am not one of them.
(Note: By Pokemon, I am talking of course about the Game Boy games, not the anime series.)
(Note 2: This contains Deathly Hallows spoilers.)
Final Battle, Pokemon Style
Harry Potter was heading towards his final confrontation with Voldemort. As he walked stiffly into Hogwart's castle, he adjusted his direction by turning precisely ninety degrees, and then continued walking still more stiffly towards the Great Hall. Harry had been preparing rigorously for this duel: he had spent the last few days walking back and forth in a small patch of tall grass near Hagrid's hut, facing off against different magical creatures. Of course, the area surrounding that small patch of grass was now littered with the bodies of the creatures he had defeated, and the smell getting rather uncomfortable by now, so he thought he may as well get it over with.
After bit of zigzagging, and wondering briefly if perhaps buying that bicycle might have been a good idea, Harry finally arrived at his destination. The Great Hall was a chaos; curses and spells flew everywhere in a scene of total mayhem and destruction, and the castle shook as it barely managed to contain a battle of truly epic proportions. Nevertheless, to someone not actually fighting, it would have seemed to be a remarkably calm and orderly situation, since the duelist looked like they were simply standing there, quite still, paired up, and facing each other. However, if you walked up to any of them and pressed the A button, you would be able to clearly their spell casting, and sometimes they may even stop what they are doing and give you some interesting, though probably useless, dueling tips.
Voldemort, meanwhile, was spinning wildly in the middle of the Great Hall... Well, he wasn't really spinning; it was more like he was randomly facing four different directions: his front, his back, left, and right. When his red eyes finally made contact with Harry's green ones, a dialogue bubble containing an exclamation mark appeared over his head, and he quickly walked up to his opponent. With his red, RED gaze still fixed on Harry, he utters the deepest and most threatening words known to men.
(Screen suddenly flashes and fades to black)
(Battle music starts!)
(Voldemort slides from the left to the top-right corner of the screen)
Wild VOLDEMORT has appeared!
VOLDEMORT: (using his trademarked cold, cruel voice) Voldemort!
(Harry appears on the bottom-left corner of the screen, squeals "Harry!" and quickly covers his mouth, not knowing what prompted to say his own name in such a ridiculous way)
(Voldemort slides through the right side of the screen and out of view) VOLDEMORT is retreating! Wait... No, he's is just sending another fighter! Go, LESTRANGE
Bellatrix: Lestrange! Lestrange!
HARRY uses POKEBALL!
(The Pokeball strikes Bellatrix and encapsulates her. It shakes for a little bit, almost as if its contents were struggling to break free, but finally stays still)
You have caught LESTRANGE!
New POKEDEX data will be added for LESTRANGE!
WICKED WITCH FROM THE NORTH
While not exactly a Pokemon, the peculiar capture of LESTRANGE has proven that Poke Balls have other, previously unsuspected uses. However, what was it that Harry Potter was thinking when he did this, we will probably never know.
Do you want to give a nickname to LESTRANGE? No? Are you sure? C'mon, you really should! Pleeeeeeeease! Please, please, please! No? Are you completely sure of that? Okay, fine... Lestrange was sent to BILL'S PC.
Bill Weasley: What the hell do I have to do with this?
(Voldemort returns, seething) VOLDEMORT uses GLARE!
VOLDEMORT's attack misses!
HARRY STICKS HIS TONGUE OUT!
HARRY's INSOLENCE has increased sharply!
HARRY uses GIBBERISH TALK!
HARRY: So, in the end, it turns out that the Elder Wand doesn't work for you, because Snape, who wasn't really its master, had always had a crush on my mother, so he has been working against you all along, and he agreed with Dumbledore to kill him so that he would have remained undefeated, except that Malfoy defeated him first, but then I bested Malfoy, so I became the true master of the Elder Wand. Aha! Take that, Tommy-boy!
Oh no! VOLDEMORT is CONFUSED!
HARRY uses EXPELLIARMUS!
VOLDEMORT uses AVADA KEDAVRA!
...but, VOLDEMORT is confused!
VOLDEMORT hurts himself in confusion!
(HP lowers to zero)
VOLDEMORT has... uh... fainted? (Please ignore the blatant use of euphemisms.)
VOLDEMORT was defeated!
HARRY gained 3.5 experience points!
HARRY grew to level 100!
What? HARRY is evolving!
He's evolving into...
Oh, wait, nope. False alarm.
You've got the ELDER WAND!... Except, of course, that it is, like, the end of the game, so you are not going to actually get a chance to use it. Oh well. Let the credits roll!
Oh, and, you got five Sickles. Yeah, Voldemort didn't carry much cash with him.
(Credits roll... But, wait, before that happens...)
NINETEEN YEARS LATER
Harry was standing on the platform Nine and Three Quarters, ready to sends his kids once more to Hogwarts. All was well... or it would be, as soon as he disposed of his most hated enemy: the Hogwarts Express.
Harry took out three Pokeballs from his belt...
"CHILDREN! Use TANTRUM!"
And thus chaos ensued as Harry finally took his revenge.
From a distance, Ginny watched proudly as her family did... whatever it was they were doing. Hermione approached her warily, a concerned look on her face, and whispered:
"Ginny, don't you think it would be better if you didn't leave Harry alone with the kids? You know, ever since he got hold of those stupid Muggle games, he hasn't really been himself..."
At first, Ginny didn't seem to notice her. However, she suddenly turned around, and as soon as they made eye contact a dialogue bubble with an exclamation mark appeared over her head. Hermione's eyes widened, but as Ginny drew her wand she realized what was going, and she did what she always did whenever this happened.
Hermione swore loudly.
(Author's note: the idea for this story came to me when I was thinking of how lame Deathly Hallows would be if it were a video game, because it would end as soon as you got the Elder Wand and then you would never get a chance to use it. Eventually, it degenerated into this... but I hope you enjoyed it nonetheless.)