Welcome again to another story! This was too good an idea to pass up. Also, as of the initial publish date at least, there aren't many good Avengers/Sonic crossovers, which is honestly kinda sad. Anyway, here's some useful notes before we begin:

- This story takes place in 2017 but is post-Homecoming.

- This is also somewhat AU: Sonic and all the anthros. exist in this universe in a separate world from Earth, called Mobius. Also, GUN exists in this universe. There are also a few more changes to the Sonic end of the -verse, but we'll explain as we go.

A quick disclaimer: Unless otherwise stated, I don't own anything or anyone here.

Chapter One

Tony Stark set down his screwdriver as he carefully inspected the hot-red gauntlet in his hand. It was just another morning of working peacefully in his workshop; just him, his inventions, and his AC/DC music he tended to leave on while he worked. This time, he'd been tuning up his latest suit, so nothing too special -unless you counted the steadily developing thoughts of creating a suit comprised of nanotechnology- today.

A rare moment of peace in a routine of meetings and press talks. When he'd finally tied the knot with Pepper, he'd consider settling down, away from the hubbub.

The inventor's thoughts shifted to the subject of a certain kid. A kid who had the peculiar hobby of running around wearing a multicolored onesie. A multimillion dollar onesie that Stark had made for him, might he add, but still. After the whole incident with Toomes and his gang and after the kid had decided to reject a spot on the Avengers team, he'd been genuinely curious as to how the kid was doing. That question had been answered when the spiderling's aunt had called and given him quite an earful about the child's rather interesting after-school hobby.

Tony wryly chuckled at the memory when FRIDAY suddenly spoke up.

"Boss, Peter Parker is requesting to see you."

Without even looking up, Tony responded by telling the AI to let the kid through. Soon enough, Peter had stepped into the workshop decked out in full Spider-Man gear.

"Good morning, Mr. Stark!" came the young voice of Parker.

"Morning, Underoos. What brings you here?" asked Stark, setting down the gauntlet as he turned to face Peter.

"Well," started Pete, somehow looking guilty even under the mask. "Please don't don't be mad, but-"

"Spit it out, Pete." said Tony, eyes narrowing.

"Well, I sorta found this little guy and he passed out, so I kinda sorta brought him here." said the spider-child.

It was at that moment when Tony got a good look at the thing Peter was holding under his armpit. It was blue, spiky, and looked somewhat similar to one of those anthropomorphic animals you'd see in a cartoon. And.. were those shoes and gloves?

"You seriously brought an alien to the tower." Stark deadpanned, having witnessed a full on alien invasion and numerous things that put just seeing one to shame.

"Sorry, Mr. Stark, I wanted to send it home, but Aunt May would've freaked out and-"

Tony cut the other off before he started rambling. "Relax, Pete, it's alright. Just set him down on the table."

The kid found the least cluttered table and did so, and Tony grabbed a rag to wipe the grease stains off of his hands.

"How did you even find him?"

"Well, I was on a morning patrol and this dude was falling from the sky," said Peter, taking off his mask as he did so. "So I saved him, but he wasn't exactly in the best condition and he passed out on me, so I decided to come to you."

Stark hummed and gazed at the hedgehog, seeing some telltale red stains on the creature's naturally cobalt blue fur coat.

"... I'll go check to see if there's any first aid."

Half an hour had passed. They'd managed to treat the blue thing's injuries, but the spiky, hedgehog-like creature was still asleep. So Stark had returned to his work and Peter had helped a bit, chatting as they did so.

"He's waking up." came Peter's hushed voice, and Tony slipped on the suit gauntlet as the hedgehog sat up and craned its neck to find the source of the words.

"Who are you?" questioned the blue creature in a youthful but decidedly masculine voice.

"You can talk?" asked Peter, excitedly. Before the alien could reply, he continued, "Great! I'm Spider-Man. The guy who, uh, saved you back there in the city. That's Mr. Stark."

The kid pointed to Stark as he said that last bit, but for whatever reason, his introduction made the hedgehog snort dubiously.

"Uh-huh. No offense, but you seem more like a Spider-Ling than a Spider-Man to me."

So the alien was not only able to speak English fluently, he was also a bucket of sass. Things just got a lot more interesting.

"See? Even the extraterrestrial creature agrees, kid." Tony quipped, deciding to get his rounds of Tony-snarking in as well.

"W-what? No, I'm not a-" the costumed one sputtered, and even though he was wearing a mask, everyone could tell that he was blushing.

"Yeah, you're not winning this one." the blue hedgehog cut in, enjoying this a bit too much. "You almost manage to sound younger than my little brother, and he's eight."

The kid just groaned and put his head in his hands, causing the alien to snicker.

"But seriously, thanks for the help." said the alien, turning his attention to the both of them and getting to his feet. "Crashing headfirst from several miles in the sky isn't exactly pleasant."

"Ain't that the truth," breathed Peter. "But, um, who are you?"

"I'm Sonic. Sonic The Hedgehog."

For whatever reason, this made Peter light up like he had an epiphany.

"Really?! That's so cool! They actually made a video game series about you!"

"Oh?" asked Sonic. "Where exactly am I?"

"Earth. Avengers Tower, to be precise." cut in Tony, before smirking. "And Underoos, that's not helping your age case."

The hedgehog's grin widened, and Peter groaned again.

"It's cool. Nothing wrong with a video game every now and then." said Sonic, taking it easy on the kid this time. "Earth, huh? It's been a while..."

The inventor tensed slightly, remembering Chitauri surrounding him from all sides.

"You've been here before?"

"A few times. I've had some crazy adventures here. Like that time a giant military truck tried to kill me."

"What." Come to think about it, he did remember something about a truck-related fiasco a few years ago.

"Yeah, I had nightmares about that for weeks."

The human shook his head before the hedgehog's stomach imitated a whale's call.

"Oh, right. Got anything on the menu?" asked Sonic. "If not, it's cool."

"I assume you eat human food?" asked Tony, to which the hedgehog nodded. "Then sure, come along. You too, Underoos."

"Wait, wha-" came Peter. Tony took off the gauntlet and gave him a pointed look.

"You told me about your enhanced metabolism, remember?"

"Oh, right."

As the trio walked out of the workshop, Tony had a question to ask.

"How'd you even sneak him past the security?"

"I'm Spider-Man." came the reply, complete with a grin.

"Smart-alec."

And that's the end of a chapter! Please leave a review if you're willing, and of your looking for another Sonic-MCU crossover, check out my other story called Phantom Gauntlet! It's basically a loose mashup of the two universes.

Fun facts: I at first wanted to write the second part of the chapter in Sonic's POV, but I decided to make it Tony-centric at the last minute. Also, Pete was at first intended to have been carrying Sonic in a web cocoon. And yes, the title is a reference to His World.

Also, this is my first time writing Tony and Peter, so any tips would be appreciated. See you next chapter!