There will be few connections to the One Piece world/characters in this FanFic. We're mainly concentrating on Luffy and his friends!
Gold watched Cebi fly about the library, while Luffy stretched his tongue out as far as possible whenever the boy's back was turned. Professor Elm was flipping through dusty old books, trying to find one that held the information he was searching for.
At last, he lifted a hefty tome from the shelf and brought it back to his desk. "So, you said your name was Luffy. And you're from Cinnebar, correct?" The professor looked up just as Luffy's tongue snapped back into his mouth.
"Um, sure! And you're the old guy who Gold said knew loads of stuff about pokéman?" Luffy leaned forwards in his seat eagerly.
The professor frowned. "I'm not as old as I look, but… yes, I do consider myself to be an expert on pokémon."
"Then why are you making Gold hunt down 256 pokémans you don't know about yet?"
Elm broke into a coughing fit. Upon recovering, he fixed a stern gaze on the rubber boy. "There are new pokémon being discovered all the time, young man! There's no way I could know about all of them!"
"So, you aren't an expert, after all!" Luffy grinned cheekily and thumbed his nose, holding out an arm for Cebi to land on.
Elm glowered at him. Another problem child… "Mind your manners. I happen to know quite a bit about over one hundred of them, at least!"
"So, you know anything about Cebi?" Luffy folded his arms on the professor's desk and stared at the chosen book.
Elm cleared his throat. "What I know isn't much, but right here, I have a book that holds all of the legends and sightings of the time-traveling pokémon, 'Celebi.' Read up!" He pushed it towards the boy.
Luffy tilted his head left, then right. "Uh… I don't get it."
"You're supposed to read it right-side up, Luffy! And hurry…" Gold pleaded. "You're wasting the time I'll have to choose a pokemon!"
"No, no! It's quite all right!" Elm flipped the book around for Luffy. "I'll give you plenty of time after we finish up here. This pokémon is incredibly rare, and I'm deeply grateful to have opportunity to see it in person!" He reached out to Cebi, who crawled further up onto Luffy's shoulder.
Luffy picked up the book and turned it over and over in his hands. Finally, he slammed it shut back on the desk. "Yea, I still don't get it."
"WHAT?!" The professor jumped out of his chair and waddled around to Luffy's side. "You don't get that this pokémon is the legendary Celebi? You don't get that most people never even catch a glimpse of it, in their lifetimes? You don't get that it travels through time, bringing ancient artifacts and futuristic devices back and forth?!"
Luffy shook his head cheerfully. "Nope!"
"You poor Celebi, forced to belong to this ignorant fool," Elm whispered.
Luffy pulled his friend away from the man's scary face. "Stop it! You're scaring her! And her name is Cebi!"
"'Cebi'? Her? Celebi is genderless! Young man, I'm afraid you don't understand…"
Luffy glared, hugging Cebi close to his chest. "Dern right I don't!"
Gold spoke up, trying to get them to stop arguing. "Luffy, it's all right. Uh... The professor is just a nutcase! So you can ignore him."
"Oh! Okay, so that's how it is…" Luffy scratched the back of his head and sat down again, relaxing immediately.
Professor Elm's face loomed in front of Gold's, larger than the boy's entire body. "What did you say?"
Gold grinned nervously, waving a hand and backing away with haste. "Nothing at all, Professor! It was nothing, really!"
"That's what I thought." Deciding to overlook the insult in favor of getting the brats out of his lab sooner, Elm clapped his hands and stepped up to the sleek white cylinder in the center of the room. "Time to choose your first pokémon, Gold!"
The boy leapt up and darted to the professor's side, gazing at the cylinder's contents with excitement. Behind him, Luffy kept turning the large book around. "How is anyone supposed to read this?"
"Ooh! I want this one!" Gold held aloft a small white and red ball. Luffy looked up at it.
"What's that?"
The professor smiled good-naturedly. "That is a poké ball, a capsule that keeps your friends in a small, confined place where they will never again see the light of day, save for when you pit them in battles against other people's friends until one or all of them faint!"
Luffy blinked. "Seriously? That's… cool! So I could put Gold in one, and he'd have to do all of that?"
"Er, no, not quite," Gold muttered. "The professor is omitting a few things. What he meant is that poké balls keep your pokémon inside, because your pokémon are your friends. I'm a friend, too, but I'm not a pokémon… And you don't let them out only for battles. You can let them out anytime, even just to walk with you… Don't you have a poké ball for Cebi?"
Luffy shook his head. "Nah. Cebi's staying with me all by herself!"
"Most witness accounts of Celebi report that it approaches people only to transport them in time," Elm mused. "Luffy, could you explain the details of how you met this pokémon?"
The boy shrugged. "She came to me, I talked to her, and then she made everything dark. That's all! Then I woke up in Gold's yard…"
Elm paled. "Luffy… what time period were you born in?"
"How should I know?" The rubber boy began picking his nose again.
Gold looked left and right at the two, realization dawning. "Oh, wow…"
"…Ah, well, we'll return to this matter later!" Elm chirped after a long pause. A gold mine. A gold mine of history, right in his lab! If only it wasn't so annoying… "So, Gold, is that the pokémon you want? The pokémon that will be your lifelong friend, partner, and companion for the rest of your life?"
Gold did a double take at the ball in his hand. "Eh? Wh-what even is it?"
"Totodile, a water-type pokémon. It and its evolutions are called Big Jaw pokémon."
Gold grimaced, dropping the ball back into the cylinder's base. "Yech, no! Is there a grass-type here?"
"Yes, look to your right. That is Chikorita. It evolves into Bayleef and Meganium."
"Huh. Those last two look too much like Tropius… I can't stand Tropius…" Gold walked to the other end of the table and peered down at the last ball. "So, then, who's in here?"
Elm frowned. "My, you're picky… That is Cyndaquil, a fire-type pokémon whose final evolution is a two-legged monstrosity. Mind you, these three are all you have to choose from, so-"
"I'll take Cyndaquil! Yay, friends forever!" Gold twirled in a circle, popping the capsule open and raising the pokémon high. Cyndaquil let loose a high-pitched squeal and fire exploded out of its back, leaving scorch-marks on the ceiling of the laboratory.
Elm tutted nervously. "Careful, now! The only reason I'm trusting him to you is because I have a mission that needs doing…"
"I'll do it!" Luffy offered cheerfully.
Elm paled again. "Er, why don't you just stay here in New Bark Town and try to act inconspicuous?"
"Insconpidicus? What's that? No, I wanna go with Gold!" Luffy raised Cebi high, like Gold and his Cyndaquil. "Cause I'm gonna be… King of the–"
"Yeah, sure. Come on, Luffy!" Gold dragged him out of the lab before the professor could ask him to help with any experiments. He'd seen what happened to Bill…
[Edited: 07-15-18]
[Original Release Date: Who the heck knows.]
Footnote: I'm purging 'nakama' from this story. Cringy as Muk. From what I remember of the blur that was me writing this, I used it at least once each chapter. I know I found it a little cringy even as I was writing it. But the One Piece fandom likes it, so I slapped it on in every time (I want to slap my younger self).