His sister (Fred Weasley x Potter reader)

We Interrupt This Arrest for a Full Moon Situation™

Before Remus could say anything else, Sirius cut him off with all the drama of someone who's been waiting twelve years to yell a plot twist.

"Pettigrew is alive, and he's right there!"

He pointed—like dramatically pointed—straight at Ron.

"Me?!" Ron yelped, nearly falling over from sheer confusion. "He's mental!"

Sirius let out a frustrated sigh and looked at me like please explain this to the child, and honestly, fair.

"Not you, Ron," I said gently, trying to soften the emotional sucker punch that was about to hit him. "Your rat."

"Scabbers has been in my family for—"

"—Twelve years," I cut in, nodding. "The twins told me. And that is a suspiciously long life for a common garden rat."

I raised an eyebrow at him as Sirius jumped back in.

"He's missing a toe, isn't he?"

"So what?" Ron asked, still entirely in denial.

I opened my mouth to answer, but Harry, apparently now fluent in plot reveals, jumped in.

"All they could find of Pettigrew was his f—"

"—Finger!" Sirius finished. "He cut it off so everyone would think he was dead! And then he transformed into a rat!"

"Show me," Harry ordered, still pointing his wand at Sirius like this was a particularly tense game of charades.

Sirius lunged toward Ron, trying to grab Scabbers, but Ron clung to the rat like it was the last biscuit in the tin.

"Give it to him, Ron," Harry said.

"What are you going to do to him?" Ron asked, still resisting, but not very successfully, because Sirius managed to wrench the rat away from him.

"Scabbers!" Ron shouted. "Leave him alone!"

I sighed and pulled my wand from my pocket. "Get off him, what are you doing?" Ron asked again.

I shot him a glare. "Shut it, Ronald, will you?"

Then I started firing off the spell we'd all practiced during our extremely niche "turn your enemy into a man" training session. To be fair, it's a very specific niche.

We missed. A lot.

But after a few rounds of teamwork—me, Sirius, and Remus all taking turns—my spell finally hit, and with a sickening pop, Scabbers the Rat became Peter Pettigrew the Absolutely Disgusting Human.

He was in filthy clothes, with yellow nails and the kind of teeth that make you want to commit a dental intervention. Sirius yanked him forward, and I did my absolute best not to gag.

"Remus? Sirius... My old friends!" Pettigrew said, eyes wide, trying for something between 'reunion hug' and 'panic sprint.'

He bolted for the door. Sirius and Remus blocked him faster than Fred and George when you're about to spill a prank plan to McGonagall.

Then he spotted Harry and instantly activated the fake sentimentality.

"Harry, look at you, you look so much like your father... like James, we were the best of friends—"

"HOW DARE YOU TALK ABOUT JAMES IN FRONT OF HIM!" Sirius bellowed, launching himself at Pettigrew and chasing him behind the piano like this was a Scooby-Doo episode.

"You sold them," Harry said coldly. "You sold James and Lily—my parents—to Voldemort, didn't you?"

Pettigrew whimpered, backing up like he could oopsie-daisy his way out of treason. "I didn't mean to! The Dark Lord... you have no idea the weapons he possesses! Ask yourself, Sirius—what would you have done?!"