Taking this chapter from one of my stories because it could fit without context… Kinda? Oh well, I have no new stories available yet, so this will have to do.
Quick explanation: Loki is living with the Avengers on Earth after everyone was brought back to life in Infinity War. Endgame does not exist.
The humans were not as bad as Loki had originally thought, though they were definitely strange. So many traditions and holidays... Loki wasn't a fan of most, but there was one such day that he did enjoy. And he actually wanted to spend that holiday with other people, thanks to Peter's influence.
~Flashback March 31st~
And as Loki's self-appointed human liaison, it was Peter's job to ensure that Loki had the full experience of the humans - including holidays of all kinds. And he was very serious about his job...
"Hey, Friday? Could you ask Mr. Loki to come here?" Peter tried not to laugh, trying to seem as normal as possible so Friday wouldn't mention anything he didn't want her to.
"Certainly, Peter," The AI responded, a hint of laughter in her own robotic voice that told Peter she knew what he was planning and approved.
With an inward smirk, he went to sit on a sofa and did his best to look distraught and hopeless with his hands holding his head up. He had spent the entire last month hanging out with the theatre club just for this moment; according to all of them, he was ready.
When he heard three sets of footsteps coming to the living room, he bit the inside of his cheek to make the tears well up in his eyes, heaving a large sigh just as the doors opened.
"No, it was really good, I mean it-" Whatever conversation the three people were having died as soon as they saw Peter.
"What happened, Peter?" Scott asked, the first to snap out of his shock most likely from his parental instincts, walking over to stand next to the boy. Loki and Tony recovering at the same time as they rushed forward as well.
"Friday, why didn't you say that something was wrong?" Tony knelt in front of Peter, doing his best to get him to raise his head.
Loki took the seat next to Peter and scanned all over him for any signs of injuries, finding nothing external. Did that mean it was internal? The worry that Loki was feeling skyrocketed at the thought, internal damage was worse than anything that would be done to the outside...
"C'mon, kid," Tony urged, "talk to us. What's wrong?"
"I- I'm..." Peter stuttered, biting his lip to show hesitance, but also causing more tears to spring to his eyes. "I'm..."
"You're... what? Kid, just tell us so we can help!"
This was it, the moment that Peter had been preparing for, for the last month. All the training and practicing and pain he went through was just for this moment... If he could not pull this off, then he was a complete failure at life.
He faintly heard the door opening as Peter let out a loud sob and hid his face in his hands, "I'm pregnant!"
It was quiet for a long time, Peter was pretty sure that everyone had stopped breathing for a few seconds. It got to the point that he was almost certain that his prank hadn't even worked and completely and utterly failed...
But then Tony stood up straight and took a deep breath. "What... the hell? Peter Benjamin Parker, of all the people I've known in my life, I expected you to be the most responsible! Please tell me you at least know who the father is? I can't believe this!"
As Tony went too take a breath, Scott decided to jump into the scolding-fest... "Don't they teach about Safe Sex in school? I know you're young, but you should know about this by now! Just because you're a super hero doesn't mean you're safe!"
The two of them went on like that for a while; it was almost like they were tag teaming each other. One of them would rant for a few minutes then take a breather as the other would build on points the prior made, or simply make new points. When Peter started laughing, that obviously didn't help the parental rage the two men seemed to be feeling and only caused them to go into even longer rants.
It wasn't until someone cleared their throat behind him that Peter glanced over to see that Bruce, Natasha, Clint, and Thor had walked in earlier. Of course, their expressions only made him laugh harder.
"Peter, stop laughing! This is serious!"
Peter held up a hand, his other holding his side as he tried his best to stifle his laughter. "S-stop, enough already...! I can't take it anymore!"
"You better take it! Raising a child is a lifelong commitment!"
"It's a prank!"
Everything went silent once again, everyone staring at him with wide eyes. Groans of realization were heard as Peter burst into giggles once again, finding this matter completely and utterly hilarious beyond belief. He had planned on simply pranking Loki, choosing the day before April Fools just in case the man already knew about the holiday, but he hadn't expected the others to join in as well - much less believe it! The Earth's mightiest heroes seemed to have all forgotten one crucial detail of the human biology...
Natasha was the first one to break the voiceless air, chuckling with a shake of her head. "I can't believe you all fell for that..."
"Hey, don't try to play it cool!" Tony turned to her, shaking his finger. "I know that you believed him too for a second!"
As the humans all started arguing about who was fooled by the prank and who wasn't, Loki and Thor shared a confused look.
"So... Peter is not with child?" Loki asked, glancing around at the others. Peter's laughter slowly stopped as he shook his head.
"No, I'm not. Females are the only humans who can get pregnant, something that all Earthlings are taught at a young age," Peter sent a teasing smirk to the others before looking back to the two aliens.
"Then why would you say that you are?"
"Because it's a prank," Peter grinned with a shrug. "Remember when you tricked Mr. Thor into thinking you were a snake when you were kids? That was a prank too, though human pranks don't normally involve stabbing."
A brightness filled Loki's eyes as he took in the information, and suddenly everyone in the room felt as if Peter had made a mistake with this... But it was too late now, the damage had already been done and all that was left to do was prepare for the upcoming storm.
And storm it did.
Loki had enlisted Peter's help - of course - and let loose a barrage of attacks on the Avengers in the Compound. Peter had taught Loki all of the basic pranks such as a hand buzzer, whoopee cushion, shaving cream in a sleeping hand. Clint had been unfortunately subjected to most of the classical pranks, despite being the one that normally set them off at the Compound before.
It wasn't until the mischievous duo had replaced the orange juice with a powdered cheese packet that the Avengers decided to start fighting back...
It started when Clint left an ad in a local news paper for a Chewbacca roaring contest with Tony's private number listed, telling people to leave a voicemail of their best impressions. The first call came in when it was 'family game night' (a tradition that Peter and Thor came up with every other Friday night). It was obvious that Tony hadn't been expecting it when he answered the call on loud speaker, his eyes going comically wide when the person on the other line started to let out an unholy roar. A string of curses left Tony's mouth as he nearly threw his phone across the room in shock, the emotion being shared by everyone else in the room. Accusing looks started being directed in Loki and Peter's direction, but then Clint started laughing like a mad man.
That was when the real war between the Avengers started.
It was absolute chaos. No one could be trusted, even with the few alliances that were formed. Loki, Peter, and Clint were the main targets, everyone deciding to take the chance for payback after everything those three had put them all through.
It was fun at first, everyone using their skills to prank each other; it was kinda a team-bonding thing... But then Natasha snuck into everyone's rooms and painted red glow-in-the-dark eyes on the ceiling. That's when it became a competition... Who could get the loudest scream from whom.
Thor, the ever gentle giant he was, filled Sam's room to the brim with some very realistic spider stuffed animals. Peter didn't think it would work at first, but didn't have the heart to tell Thor that (Loki was another story completely). But after he had helped Thor buy all the stuffies and placed them around the room, he was roped into hiding underneath them all to wait for Sam. It was actually kind of fun, and when he heard Sam's footsteps coming to the room he stilled his body as much as he could to not give anything away.
To this day, Peter had never heard a grown man scream at such a high pitch in his entire life. Somehow Thor had found out about Sam's fear of spiders and exploited it to the max. Loki - who was reading in the next room - had nearly fallen out of his chair at the scream, thoroughly convinced that the two had done something unthinkable to the poor man. Though it could be argued that using someone's phobia in a prank was unthinkable...
After the dust had settled with Thor's prank, everyone was anxious to see what would happen next - praying that the two scientists would sit this war out... Tony and Bruce were geniuses and could probably do some seriously extreme pranks if they so chose. Tony could be a mad scientist that might find a way to humiliate and terrify them at the same time with very little effort; Bruce could be just as bad (if he could get serious about it). It was absolute hell waiting on them...
Thankfully (for them) they didn't have to wait long for Bruce. The man had tried to serve them all exploding milkshakes that ended up backfiring on himself, covering him and any nearby surfaces with the cold and sticky drink. Some had landed on a target though; Loki's pants and shirt had little pink spots covering his side. It had been a good laugh, especially when the shake had dripped off of Bruce's face enough for everyone to see the shocked expression he wore.
After a few more pranks, everyone was growing more and more uneasy. The war had been going on for a week; it was slowly starting to tamper out... It was mostly just a few little revenge pranks here and there. But what had everyone on edge was that Tony had yet to prank anyone, not even a small practical joke! Everyone had thought that he would have been one of the first to think of the best and biggest thing, but he just sat with everyone and laughed at whatever jokes were pulled.
"Alright," Rhodey stood up abruptly, causing a few people to jump. "What the hell, Tony? We're all waiting, but there's still no prank from you! As much as I hate all of this, just get it over with already!"
Everyone's eyes were drawn to Tony, a smirk slowly spreading across the man's face as he leaned back in his chair. "What makes you think I haven't done a prank yet?"
"You have?" Peter tilted his head, his eyebrows furrowed slightly.
"You all assumed that I haven't set anything up yet, but maybe my prank takes a certain number of... triggers to set off? Such as passing in front of it or touching it?"
All eyes were wide with unimaginable horror as they gazed at Tony, Peter taking extra measure to step back with a hand on his chest.
"Mr. Stark... That's so evil..."
"Evil," Loki nodded, a smirk playing on his lips. "But genius. I like it."
It had been months already, but no one had yet to run into Tony's prank yet... Most of the team had forgotten about it or were no longer concerned.
That day Loki was hanging out in the gym, where most of the Avengers were working out. He would have been in his room reading or something, but Peter made him promise to watch. Apparently the boy had been working on some new move that he wanted everyone to see.
While waiting for the rest of the team to get there though, Peter was taking a run through the parkour course that Tony had set up for him. Loki chuckled as he returned to his reading on the sidelines.
Tony had just walked in the room when it happened.
A high pitch scream that rivaled Sam's.
Everyone (minus Tony) ran to the locker rooms to see what happened, only to stop short at the sight before them. Peter was the first to recover as he saw Captain America's bewildered and terrified expression as he was caught up in the middle of what could only be Tony's prank.
Steve's expression soon changed to a playful rage as he started to make his way to the gym, everyone giving him a wide pathway.
"Stark! I know this was you!"