*Potter Puppet Pals belongs to Neil Cicierega and One Piece belongs to Eiichiro Oda. This plot follows as close to "Ron's Disease" as much as possible with a few edits to better fit One Piece circumstances. I tried not to have anyone too out of character and I do apologize if it was worse than I thought.
Also, would this count as a crossover? I'm unsure on how to categorize this...*
Trafalgar Law leaned back and stared at the clouds that floated in the sky over Amazon Lily. "What a beautiful day today," he commented to nobody in particular.
"Everyday's beautiful when you're here, Captain!" Bepo piped up, "But…"
Law slowly turned to stare at the polar bear dead in the eye. "But what, Bepo?"
Bepo, knowing that he'll be in for it big time if he lied to his captain, lowered his head in gloom. "I've got a secret affliction…"
"Disgusting!" two men in boiler suits shouted. "First you're showering all of us with your sweat and now you've caught something weird from this island!"
"You don't even know what it is yet!" Bepo protested. "It's lice!"
The two men jabbed their finger toward the sea. "Get. Out."
"It's pirate lice!"
"Did someone say lice?"
Everyone turned to see a shirtless old man rise out from the ocean. The old man was none other than Silvers Rayleigh.
Bepo raised his paw, "I did!" He turned towards the two men and whispered, "How did he know?"
They shrugged. "This is Rayleigh we're talking about. I heard he's not even fully human, but that he's a cyborg."
Rayleigh walked over to Law. "Young man, you need to help your crewmate here. Another infestation is the last thing your ship needs."
Law stood up and stretched. "I don't like to take orders from anyone, but you're right. I don't want this to start spreading to everyone."
"Good. Now, since lice are heinous little pirates, you'll need a heinous big pirate. Find the giant Jean Bart. He'll know what to do.
"Jean Bart? All right. Let's go, Bepo."
Bepo trotted in step with Law. "Hooray!"
"Don't do that."
As the Heart Pirates got ready to go to find Jean Bart and to cure Bepo, one member wearing a large hat stopped and asked his companion who wore a penguin hat, "What did he mean by 'another infestation?' What was our last one?"
The man with the penguin hat thought about this. "You know, I don't even remember if we ever had one. It sounded more like he was just reciting something from a script."
Law and Bepo entered a dimly lit cave.
"Jean Bart, are you here?" Law called out. No answer.
He sighed. "What kind of giant lives in a cave? I didn't know that a cave big enough to house a giant could even exist."
"Oooh!" Bepo pointed excitedly at a dark corner of the cave, "A suspicious mound that's slowly rising and falling! May I jump on it?"
Law looked at his subordinate long and hard. He looked at the mound that looked like it was breathing. "Sure. Do whatever you want, you diseased bear."
"Diseased bear? I'm sorry…" the bear slumped. And then a fist pummeled him into the opposite wall.
"Quit making all that noise, I'm trying to sleep!" the mound shouted.
Law grinned. "Ah, Jean Bart, we need your folksy advice. Bepo here is infected with pirate lice."
Jean Bart, his mouth stuck in a position where his teeth was always bared because he didn't listen to his mother who warned him about how faces can stick a certain way if you're not careful, glared down at the pirate captain. "Aren't you a doctor?"
"I am. Except Rayleigh said to see you."
"Why would he say that? I have no knowledge of medicine whatsoever."
"So I wasted my time getting all the way over here," Law frowned. "I'm not in a very good mood right now, Bepo, so let's just shave you bald and get rid of the lice right here and right now."
Bepo hugged himself and began screaming.
"Well," Jean Bart scratched his chin, "There's another way…But you're not going to like it."
Bepo stopped screaming and looked up. "Eh? Is it really that bad?"
Less than a second passed after he said that when he took Jean Bart's right hook straight in the face.
"You're cured," Jean Bart dusted off his hands, "I knocked the lice out of you."
Hmmm, Law thought, with the help of Jean Bart's sheer brute force, I could get a lot of my problems solved. "Say, Jean Bart, how would you like to come with me? And bring your muscles, too."
"Why should I?"
"Fair enough. This cave sucks, anyways."
The former marine officer stopped walking to stare at the Surgeon of Death. And then at the giant.
"Guess how many people my giant has punched," Law continued, "Two. The first one was Bepo. And the second one-"
Jean Bart socked X. Drake so hard he went through a brick wall.
"-is you." Law turned to the giant. "Nice work, Jean Bart. Let's keep going."
Eustass Kidd glared at Law. "What the hell are you doing here, Trafalgar Law?"
"Oh, nothing. Just having my newest crewmate punch you in the face."
"Wha-" Kidd's mouth opened just in time to get a giant fist rammed into it. "What the hell? You trying to start something you damn pun—"
"He's still got some lice. Hit him again," Law cut in.
That punch had enough force to send the redhead flying.
Law smiled, satisfied at the results, and continued on.
Admiral Kizaru could not believe his luck. Trafalgar Law was just walking by casually.
"Trafalgar Law~" he droned, "I'm not going to let you get away again~" He aimed his pointer finger at the pirate, fingertip glowing like a firework.
Law just continued walking. "Not today, Kizaru. I've got some more important things to do."
Kizaru, being kind of slow, stood there for a few more minutes before he fully realized what had happened.
"Hmmm~?" he mused. But Law was already long gone.
"Ah, you're back," Rayleigh greeted them, "Did you cure your friend of his lice?"
"You bet I did!" he nudged Jean Bart with his nodachi. "Hit!"
Jean Bart launched a giant fist straight into Rayleigh's gut, but the old man didn't even move an inch. A loud resounding clang echoed in the air.
"Ooh, trying to take a whack out of the old ex-pirate, eh?" he jovially asked.
Law was stunned. "No way…He's an android!"
Rayleigh nodded. "That's right. I am an android. A ship-coating android."
"Suuuuppppaaaahhhhhh!" Franky cheered and then he and the old man started dancing to some tune that only they seemed to be able to hear.
At this point, Law left because this story no longer made any sense. But not without having Jean Bart drop kick the author and now said author can no longer continue writing due to a lack of consciousness.