Hey, guys. I came up with this on a whim, so I'm writing it to see how it goes.
Disclaimer: I do not own Pokémon or Batman: Arkham CIty

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Arkham City. A place where only the ruthless and the smart survived. Most were more of the first than the second. Not even supervillains had escaped the daily struggle to survive. Of course, the three-way gang war going on didn't help either. Or it did, depending on your point of view. None of this mattered, however, to the purple figure that appeared from a portal in the sky above Arkham City. It managed to stay up for a while, before it began to fall to the ground. The round being felt the air whooshing past, barely keeping conscious, before managing to steer itself into a pile of snow. As it lay there, its vision dimmed. A feeble cry managed to escape its mouth before it passed out. "Geenn…garrrr…."

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As Batman made his way to Penguin's museum, a radio transmission came through on Puffin-One. "Hey, boss, we found something weird here in the snow. It's some sorta creature or something."

"Did you now? Well, what are you waiting for? Bring it 'ere! If it's something I ain't seen before, you lot might get a promotion. If not, well, ol' Grundy could use some exercise. Got it?"

"Understood, boss"

As the transmission ended, Batman wondered what it was Penguin's thugs could have found. 'If Cobblepot wants it that badly, I may just have to liberate it from him.'

Batman was not the only one who learned about the creature. Catwoman was heading towards Poison Ivy's lair when she saw Penguin's thugs carrying a strange creature. For some reason, it looked familiar. 'Well, that certainly is strange. Red can wait. I need to see what this creature is.'

Penguin's museum had attracted quite a few characters tonight.

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When the thugs reached Penguin's museum, they entered quickly, hoping this strange creature would please their boss. As they went in, they were greeted by another thug. "What da heck is dat?"

The leader of the patrol answered him. "Hey, Ricky. We found this out in the snow, some sort of creature. We're not sure what it is."

"Lemme see." Ricky pushed a few thugs out of his way. When he saw the creature, his mouth hung open in shock. "I'll be damned. Dat's a Pokémon!"

"A what?"

"A Pokémon. You know, da creatures dat look like animals and plants, but they ain't?"

"You mean that yellow mouse that can shoot lightning?"

"Yeah, dat."

"Huh. So, you know what Pokémon this is?"

Ricky scratched his head. It had been awhile since he had messed around with the Pokémon TV show and the cards. Round body, purple coloring, spiky back, Cheshire cat grin...

"Well, I can't remember it's name, but I do remember da type."

"The type?"

"Yeah. Pokémon have different types. Can't name dem all at da moment, but dis one is a Ghost-type. Ghost and something else. Poison, I think."

"Huh. Well, we gotta get moving, Ricky. We told the boss that we would bring him the creature...er, Pokémon."

Ricky waved his hand, shooing them in a sense. "Go on, and don't worry about its name. It's da only thing it'll be able to say."

"Alright. Thanks, Ricky."

"No problem."

The thugs walked off, having received Pokémon 101.

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Penguin walked to his balcony over the Gladiator Pit. Normally, he'd be indulging himself at the Iceberg Lounge, but his goons had just entered the museum. He hadn't seen the creature, but his men looked like they were carrying something heavy. 90 lbs., maybe? Didn't matter. This creature had better be an interesting one, or they'd get it. He'd give them a choice at least. Tiny, or Grundy. He snapped his focus back towards reality as the thugs entered. "Here it is, boss!"

Penguin blinked in surprise. He really had never seen a creature like this. "Well, what is it?" he snapped.

"We passed Ricky on the way here. He says it's a Pokémon. Some sorta poisonous ghost, or something like that."

"A Pokémon, eh? All I remember about Pokémon is that they can battle. Wake it up!"

The lead thug nodded, signaling to his patrol to drop the Pokémon. It hit the ground with a heavy thud. "Garrr..."

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"Owww..."*

He sat up, rubbing his head and frowning. Where was he? He opened his blood-red eyes and looked around. Some sort of pit, with humans in it. Above him was a balcony, which had one human. An ugly human. It reminded him of a Drowzee, with its leering eyes. "'Ello, sunshine. I 'ear, you're a Pokémon."

He blinked. Of course he was a Pokémon! How could this human not know what he was? "Now, I only know one thing about Pokémon. And that's that they can battle!" The ugly human opened the gates.

"Now then, whatever your name is..."

"Gengar."*

"Eh?"

"My name is Gengar."*

"Gengar, eh? Alright then, Gengar, if you can survive this, I'll let you join my collection. Get 'im, boys! Initiation, part one, 'as started!"

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Well, that should serve as a good cliffhanger. Let me know what you guys think about the story. See y'all next chapter!
*Translated from the Pokémon language