Imagine If You Assembled The Avengers: Volume 3

But He Started It (Stony x reader)

Steve/Tony relationship

"You're a butthead!"

"Watch your language, you jerk!"

"Shut up!"

"I'm gonna tell (Y/N)!"

"Go ahead, you big, spangled baby!"

"Oh, I'm gonna!" Steve snorted, sticking his tongue out at Tony as he stomped past him.

This might have been a hilarious scene to witness, had you not been soundly asleep and about to be disturbed after a mission that had kept you awake for over twenty-four hours. It could have been almost cute, given that the two Avengers arguing like children were just that; Steve and Tony had been caught in the crossfire of a spell gone wrong during a raid of a Hydra experimentation base, and were now running around the compound as five-year-old boys while Wanda worked furiously to figure out a way to undo it. It had gotten to be so intolerable that Thor had just left to seek out Loki's help as well.

You had been lying in bed for merely an hour, hearing the melee going on a few floors below; even as children, Steve and Tony had voices that carried through the building like they were standing right next to you. You had gone to bed with the full expectation that it wouldn't last long, but now that your body had found relaxation on the mattress, and you had just gotten warm in the hug of your blankets, you didn't care how long they would stay this way, so long as you were allowed to sleep more than the blink of an eye.

"(Y/N)!" Steve yelled to you through the door, banging his shrunken hands angrily against it. "(Y/N)! Tony called me a butthead!"

"Ugh, fiiiiine," you groaned, tossing the blankets back to uncover your head and yell in reply, "what did you do to deserve it?"

"I didn't do anything!"

"Steve..."

"I didn't!"

"I can tell that you're lying, Rogers. Spit it out."

There was a long pause before you heard his answer, and he gave away his guilt without so much as a peep from his voice. It wasn't often that Steve Rogers was caught in a lie, at least not as an adult; however, this Steve was something new that you hadn't encountered before, and you were learning new things about the Captain by the minute.

"I...I uh..." he coughed quietly, "I might have...uh...put peanut butter...in...uh, in his helmet."

"Steven Grant Rogers! You didn't!"

"But he started it!" he began again, re-energized. "He put goo all over my shield so I can't pick it up anymore, and I can't wash it off!"

Taking a long, deep breath, you pushed yourself up to sit on the edge of your bed, considering if you really wanted to get up and tackle this new emergency. Wanda was here, working on fixing their affliction, so Vision wouldn't be far away; he could watch the little troublemakers. Thor was due to stop back later in the day as well if he could track down his brother, and you swore you heard Sam's voice a few minutes before you dropped into bed. However, even though those other resources were there, you knew that it would all come back around to you anyway, and to stay in bed would only delay the inevitable and would only make you angrier in the long run. Sliding your feet into your slippers and standing with a long yawn, you made your way to the door to open it. Out of habit, you looked up to where Steve would normally be looking back, only to giggle under your breath when you looked down at his smaller version.

"Stop laughing," he whined, "it ain't funny."

"Steve, what would you need your shield for anyway? Can you even lift it anymore? And Tony's too small to fit into the helmet now, so your prank totally backfired. All that you guys are doing is pissing everyone else off."

"He started it!" he repeated, with a petulant stomp of his foot. At any other time, the little pout he was giving you would be cute, even with the fire of red in his cheeks.

"Aww, Stevie, come here," you cooed, reaching down and lifting him up before he could get away. Even as you steadied your grip, he was trying to thrash himself free, but you weren't having it. "Come on, little fella, let's go."

"Maybe you're the one who's a butthead," Steve mumbled under his breath as he gave in. He put an arm around your neck and held on, keeping his legs around your waist so that he wouldn't fall. It was definitely an uncomfortable situation for you both, but in a welcome moment of understanding and agreement, you held back your laughter and simply made your way to Tony's lab without a word.

~~~

"Bruce, write this down, word for word. I, Anthony Edward Stark, think that Steven Grant Rogers is a butthead-"

"Yes, Tony, we all heard that already," the doctor whined. He dropped himself heavily onto one of the stools at his workstation, exhausted and barely holding up his own head in his hands. "You need new material."

"Okay, he's a spangled-"

"Baby, we know."

"Well if I swear, (Y/N)'s gonna spank me!"

Bruce's eyes lit up with mischief, turning to the small scientist next to him with a chuckle, "you sure that's not what you're aiming for here?"

"Hey! I know that Cap's not my favorite person at the moment, but we're still...us...I think? Do you think?"

"Well, if we can't get you back to adults, I'm not sure if there are laws in New York for this sort of thing. Besides, I don't think that lubing up his shield is grounds for divorce." His voice had barely faded away before Bruce could regret his words, at the sight of Tony's smile growing and his eyes twinkling at his friends unintentionally perfect choice of phrase. "Tony-"

"Pfft, you said lubing."

While Bruce all but curled up into a ball of embarrassment, you passed through the lab door with a resistant Steve still on your hip; as soon as he saw Tony, it did nothing but re-energize his annoyance, but you were ready and quickly shut him down. "Stark, sit," you ordered, setting Cap down on one of the stools opposite of him. Tony struggled a bit, his foot slipping off from one of the lower bars and tipping the seat off balance. "Need some help, little man?"

"Piss off."

"Hey," you pointed sharply, "what did I say about language?"

"I'm still a grown up! I'm just smaller! I can swear if I want to, and besides, that wasn't even swearing! You're being mean!"

"She's right," Steve joined in, "you swear too much, Tony. Even as a grown-up, it's pretty bad. When we have kids, you're gonna have to reel that in."

Tony was about to offer yet another snappy comeback or sarcastic comment of his true, epic proportions, but instead his mouth hung open in surprise at what Steve had said. The two of them had their disagreements even as adults, and this terrible change of events had them both at the peak of frustration and found them taking it out on each other. Tony realized that taking it out in pranks and picking on each other was their way of coping, even as kids, because they knew that it didn't really mean anything, and the other would roll with it without taking it to heart. It meant that they were matched up pretty perfectly, and he began to worry.

"So...we're..." he paused, pointing back and forth between them, "we're still having kids? W-we're good?"

"Yeah, of course," Steve shrugged, "so long as you clean the lube off my shield."

"You said lube," you snickered under your breath, only to be silenced by Tony's look of unexpected disgust. You thought for sure that of anyone in the room, he would've at least laughed out of pity for your poor timing if not for the agreement you were aiming for. "Right, uh...sorry about that."

"And I'll take care of the helmet," Steve continued, but you could've swore you saw the hint of a smile under the façade. It was remarkable how different they both were in this age, but you still weren't willing to let it go on much longer just to find out more.

"See?" you smiled with a happy clap of your hands. "That was easy! Once we get you two back to normal, and a few years have passed so we all get to forget this abysmal experience and what little terrors you both actually are, and with the understanding that I'll never, ever babysit, you two could totally have kids someday!"