Peter Parker was many things.
Recent High School Graduate. Empire State University full-ride scholarship recipient. Genius.
Spider-man. Mentee to Tony Stark. A superhero in the making.
He was a nephew, a best friend, a boyfriend, a protégé. A big brother.
But at this precise moment, he was so much more than that.
Peter Parker was totally, utterly screwed.
This was largely because, of all the things he was, he was worst at being a big brother.
"Morgan!" he called for what had to be the fiftieth time, looking under the large couch in the middle of the Stark's living room for what had to be the fifteenth.
"Oh, man," Peter groaned when the bubbly two-year-old he was searching for was, unsurprisingly, still not hiding under that particular piece of furniture. He tugged on his hair as he slowly turned in place, gaze roving over the completely silent room. "I'm going to be in so much trouble when Mr. Stark gets home."
This was bad.
The Starks rarely went out without their precious, still extremely young daughter in tow. It had been a hectic two and a half years (give or take a few months) since the defeat of Thanos; and after Pepper had finally been able to tell Tony that she was pregnant, he had actually resolved to retire as much as the world would allow him and dedicate his time to their growing family. Peter was just happy that that somehow still included him—that with a wife and a baby, Tony still had time to mentor him. To be a father to him.
And with great power comes great responsibility, so if Mr. Stark was going to treat him like the son he never had, that meant Peter had to treat baby Morgan like the little sister he never had.
So he had been pestering Tony and Pepper for months now, trying to get them to trust him enough to leave Morgan in his care while they took some time for themselves. To have a moment of true peace between just the two of them for the first time since Thanos destroyed half the universe (which, the Avengers were able to fix, of course, but that wasn't the point).
And this was the day. Mr. Stark had asked him a week ago to babysit his daughter while he and Pepper did… well, Peter wasn't really sure what they were doing. He just knew that Morgan had been entrusted to him for the evening, and he was seriously messing that up.
If he didn't find Morgan before her parents got back in approximately 30 minutes, he was dead.
Well, not dead per se. But Mr. Stark would definitely never trust him again and he would be deemed the worst sort-of-big brother in the universe. And that was basically the same thing.
"Come on, Morgan! I give up. You can come out now!" It was back to her bedroom now, where he looked under her bed, in her closet, in the toy chest, in every conceivable hiding place he could imagine. But it didn't matter. Mr. Stark had warned him, but he hadn't listened.
"Ollie ollie oxen free!" he tried as a last ditch effort, but he knew it would be pointless. Morgan Stark was simply the best hide-n-seek player to ever live, and Peter should have heeded his mentor's warning and never agreed to play.
But come on! She was a tiny, adorable two-year-old! How could she be that good at hiding?
Granted, the Stark's home was basically a mansion, with three-stories and roughly 8,000 sq. ft. of floor space. In an attempt at fairness, Peter and Morgan had agreed to stick to the main level for their game. However, Peter had the feelings that agreements made with toddlers were likely to hold little value, so he had painstakingly searched every floor, every room, every crevice for the past two hours. Yet, still no Morgan.
It was insane.
He was Spider-man for crying out loud! He caught criminals on the daily and occasionally even helped stop genocidal maniacs from destroying the universe. Finding a two-year-old should not be nearly this difficult.
He was out of options and out of time. Mr. Stark would be here any minute and he would have to tell the man he looked up to most in the world that he had lost his only daughter in the span of four hours.
There was only one thing left to do.
"Morgan," Peter pled, dropping to his knees on the hardwood floor of the living room. "Please, Morgan. You gotta help me here. I give up. Please come out now."
He ignored the sting of embarrassment that came with begging a two-year-old for mercy and continued to analyze his surroundings. Everything was still deathly still, his enhanced senses not picking up any sound or movement.
That was it. Nothing could save him now.
Sighing in resignation, Peter climbed to his feet again and dejectedly made his way to the kitchen. This was a stressful situation after all, and stressful situations called for copious amounts of food.
He checked his phone for the time as he strode into the kitchen.
8:47 p.m.
Thirteen minutes. He only had thirteen minutes left to live without the terrible shame of Tony Stark's disappointment.
His movements were sluggish as he grabbed a bowl from the cabinet and a box of cereal from the top of the fridge, the first edible thing he laid eyes on.
It was Coco Pebbles. Peter's favorite.
He knew that Mr. Stark kept that particular cereal in his house for solely that reason, which made his failures as a babysitter, and more importantly, a self-proclaimed honorary big brother, so much worse.
"Ugh," he moaned, shoveling a spoon-full of the delicious cereal into his mouth as soon as the milk had been poured. "Now I have to tell Mr. Stark that I lost his daughter in his own house and he'll never trust me to watch her again," he mumbled around his cereal, staring sightlessly into the depths of his bowl.
He was most certainly exaggerating, but come on—he was an eighteen-year-old who knew he was about to disappoint someone who's approval meant everything to him. Not to mention he had just temporarily misplaced his favorite toddler. Things were not looking good for him at the moment, and he only had approximately 11 minutes left to pity himself before he had to face the music.
He heaved another world-weary sigh before stuffing his face again. "I probably won't be allowed to play with Morgan at all anymore."
"No!"
Peter jumped in the chair, twisting around to face the cabinet above the refrigerator—the direction the small, panicked voice came from, where a head of messy, dark brown hair was poking out.
"Morgan!" the teen cried out, jumping to his feet, doomsday snack entirely forgotten.
"I sorry, Petta!" the young girl babbled as she attempted to clamber down from her hiding place. She had just crash-landed on top of the fridge when Peter reached her, pulling her down and placing her safely onto the chair that he had just vacated. "I don' want you to be in trouble. I's just playin'!"
Peter stared at her with wide, almost shell-shocked eyes. He had checked that cabinet—multiple times. He knew from experience that it was one of her favorite places to hide.
"Morgan," he asked the toddler hesitantly, watching her with narrowed eyes as she determinedly gnawed on his abandoned spoon as though she would disappear before his eyes again. "Were you up there the whole time?"
The toddler giggled, her green-eyes shining brightly at him as she took the spoon out of her mouth and started drumming a complex beat on the table. "Nuh uh."
"Nuh uh?" he asked before taking the spoon away from her, belatedly realizing that it was probably not something she should be playing with.
Morgan pouted, as she was prone to do, but didn't protest his thievery otherwise. "No," she clarified. Sort of.
Peter laughed, scooping the girl up into his arms and taking her back into the living room to wait for her parents. "Then where were you? I've been looking everywhere for you, Iron Baby!"
Morgan shrieked in joy, as she usually did when Peter called her by the nickname he had given her (which had been quickly picked up by the other Avengers, much to Peter's pleasure). "I know! I was hidin' from you!"
"But I looked everywhere!" Peter protested, gently tossing the toddler onto the plush couch. He waited for her giggling and bouncing to subside before asking, "How did you stay hidden that long?"
Morgan looked at him with wide eyes, worryingly still and silent for a long moment. She looked first to the left, then the right, as though she was making sure they were still alone. Peter just raised an eyebrow, waiting for the show she was putting on to end.
Eventually Morgan deemed the living room safe and motioned Peter forward with chubby hands. Once he was crouched in front of her, she leaned in even closer and asked, in what was perhaps supposed to be a whisper, but was actually a touch louder than normal, "Can you keep a secret?"
Peter made a big show of checking their surroundings again, looking all around the room before nodding and loudly whispering, "Pinky swear."
As soon as the ritual pinky-swearing was completed, a mischievous smile—one much too evil to be found on the face of a two-year-old—spread across Morgan's face. She leaned in even closer, as everyone knows the closer you are the more secret it is, and said, "F.R.I.D.A.Y."
Peter was only confused for a moment before comprehension dawned on him and he jumped back and explained, "F.R.I.D.A.Y. helped you win!"
Morgan simply nodded, looking entirely pleased with herself. "Uh huh."
F.R.I.D.A.Y. was, of course, always monitoring the Stark household, so it made sense that the AI was capable of tracking Peter's movements and warning the youngest member of the Stark family so she could relocate herself. It was completely plausible. He just couldn't believe that a two-year-old had thought to use it to her advantage.
When Peter didn't say anything while he processed this new information, Morgan grew concerned that her brother was not a reliable confidant after all. "You can't tell Daddy, Petta. You promised!"
"Of course not!" Peter assured her, crouching in front of her once more so she could clearly see his grin. "We pinky-promised, remember?"
Morgan returned his grin, nodding enthusiastically. "Now we can both hide from Daddy whenever we want!"
Peter had just began contemplating the possibilities of such an arrangement when the Starks returned, their entrance made obvious by Tony's loud exclamation of, "Where's my girl?"
Morgan squealed and hopped off the couch, running as fast as her chubby legs would take her to the foyer where her parents waited. Tony was crouching with his arms wide-open, waiting for the incoming hug from his daughter who he was clearly relieved to see was still alive and well.
"Mommy! Daddy!" said girl cried as she darted under Tony's outstretched arms and launched herself at her mother.
Pepper, of course, was delighted to be the parent of choice for the evening, but Tony pouted, causing Peter to grin and step forward with his own arms open.
"Mr. Stark?"
Tony looked away from his embracing wife and daughter and immediately rolled his eyes and stood up. "I'm alright, thanks kid."
"Aw, come on, Mr. Stark," Peter goaded, stepping forward. "We were both so good!"
Tony scoffed, but reached out to pull Peter into a quick one-armed hug. "I really doubt that, Spiderling."
He stepped back from the hug, but kept one arm around Peter as they turned to face the other members of their little family. "What do you think Pepper? Were they good?"
Pepper, who was holding her jabbering daughter, smiled and moved to leave the foyer. "I don't know. Let's see, shall we?"
They moved as one through the living room, making sure that nothing had been destroyed in their absence. When everything checked out, Pepper smiled down at her daughter. "It looks like you were a good girl for Peter after all, darling." Morgan only giggled happily in response, and Pepper turned to Peter and said, "Thanks again for watching her for us Peter. We really appreciate it."
"Oh, no problem!" Peter said, feeling like he could breathe easily for the first time in an hour. The Starks were back, Morgan had been found, nobody had died, nothing was broken. It had been a good night. But he wasn't about to push it. "Well," he said, grabbing his backpack that was waiting by the couch, "I'll just head out then."
"Not so fast," Tony said in a tone of voice that instantly made Peter freeze.
Peter turned slowly, internally cringing. He knew that voice. And sure enough, Mr. Stark was making the face that usually accompanied it. The one he always made when he thought they were hiding something from him. It was what Peter privately referred to as his Dad Face, and it was truly fearsome.
He was so busted.
"F.R.I.D.A.Y."
"Yes, Mr. Stark?" the AI responded while Peter started praying.
"Did anything of note happen while we were gone?"
Peter held his breath, not daring to make eye contact with Mr. Stark while he waited on F.R.I.D.A.Y to rat him out for temporarily losing Morgan… for two and a half hours.
Did Peter mention that he was so dead?
"No, Mr. Stark. There are no incidences to report."
Peter almost couldn't believe it and he audibly breathed in relief, probably not helping him seem less guilty. Morgan, however, smiled angelically at Peter, and he imagined that if she knew how to wink at him, she would have in that moment.
"Daddy! Daddy!" she cried after F.R.I.D.A.Y. gave the all-clear, clambering out of her mother's arms and running across the room into her father's.
Tony smiled at his daughter, though he still seemed to be on edge, as though he was waiting to find out that something catastrophic had happened in his short absence, despite everything seeming perfectly fine. "What is it sweetheart?"
"Petta and I had soooooooooo much fun! Can he watch me again?"
Tony pouted theatrically. "Aw, really? We let the kid watch you one time and now he's the only one you want to play with?"
Morgan chortled and grabbed her father's face to smush it between her chubby hands. "Don' be silly, Daddy! I wanna play with you too!"
"Well," Pepper said, moving toward the staircase with a soft smile, "you can all play, but I'm going to bed. Goodnight darling!" she called out, blowing the still-rambunctious toddler a kiss before ascending the stairs.
After everyone had called out their goodnights, Morgan turned back to her father with her normal, face-splitting smile. "So we play now, Daddy?"
Tony sighed dramatically, but agreed. "Yes, Morgan, we can play now. But just one game."
"Yay!" the girl cheered, clapping excitedly before she squirmed out of her father's arms to run to Peter. "We play hide-n-seek?"
Tony narrowed his eyes at his kids, knowing a trap when he saw one. "Morgan, you know that we can't play hide-n-seek. It takes way too long."
"Nuh uh," Morgan said, eyes too-wide as she rapidly shook her head. "I'll hide with Peter, so it'll be easier to find us. He not very good."
Peter bit his lip to hide his smile as Mr. Stark contemplated them, deciding if he should just agree to avoid the tantrum or press for a different game to spare himself the torture of playing hide-n-seek with his devious daughter. Peter wasn't going to let this opportunity pass him by that easily though. "She's been begging me to play all night, Mr. Stark. I think that we should play with her."
Tony considered it for only a moment more before reluctantly nodding with a sigh. "Fine. But just because I know that you are a terrible hide-n-seek player, Pete."
Peter nodded in agreement, only barely managing to hide his smile as Mr. Stark turned around and began to count to one hundred.
Morgan grinned up at him and took his hand as soon as the countdown began, running with him to their first hiding place of the night.
It was a challenge to keep the talkative child quite as they moved from spot to spot, but she was definitely a pro with F.R.I.D.A.Y. whispering to her from seemingly nowhere. No wonder no one was ever able to find her.
Peter's family had never been conventional, but that was okay with them. He had lost his parents and his uncle, and for a long time it had felt like it would only be him and May against the world. But things changed, and families didn't have to be nuclear to be meaningful.
He still had May, but he also had Ned and MJ, and Mr. Stark and Pepper, and the rest of the Avengers.
He also had someone he could consider a sister now, something he never thought he would have, but she was something he was unquestionably grateful for. Especially when they were curled up in a cabinet together, with Morgan asleep next to him while Mr. Stark grew increasingly more frustrated as he combed through their house, calling out for them in desperation all the while.
He couldn't remember the last time he played hide-n-seek, but he knew that it had never been as fun or as sweet as this.
A/N: I hope you liked this! It was just a fun idea I had, and I definitely needed some fluff in my life so. At this time, I'm thinking this will be a oneshot, but if I get a good response I would probably be happy to make it a series of short stories following Peter and Morgan's shenanigans. So if that's something you're interested in, please let me know!