{A/N} In this one-shot, Tony is just Peter's mentor like in the movie, but they do have a kind of father and son relationship. This is also after the Civil War. Remember, Peter isn't adopted, but don't worry ＼(★^∀^★)／
3rd Person POV
It was a normal day at the tower. Tony and Peter were playing with LEGO, Tony was worried about the civil war which happened between his crew and Steve's one. Oh god, why didn't he just agree with him at the start? The Avenger's break up would have never happened. If only he had endorsed the treaty.
Tony groaned and continued on building the LEGO spaceship with Peter. Suddenly, Friday reported Tony about meeting Steve and the rest of the group. Oh no, how could he have neglected that information? He started to panic; what if it turned into a roaring argument? What if it would turn out inopportune? Peter looked at his mentor and tried to comfort him.
Through those doors were the Avengers. They all looked at the pair in a confused look, Peter turned to see them, his eyes widened. "Don't just stand there, gawking at us! Get a glass of water," Peter ordered. Steve ran to the sink and grabbed a glass full of water and ran back to Peter. He held the glass and Peter took it and let his mentor drink it.
Tony returned to his consciousness and rubbed his temple. "Did I just get drunk?" He questioned and everyone began to chuckle. Steve then hugged Tony.
In A fRiEnDlY wAy, SoRrY sToNy ShIpPeRs
Steve then cocked his head upwards to face Peter, he smiled at him. "So, who may you be?" He held his hand out and Peter took it. "My name is Peter Parker, I'm Mr Stark's intern." They shook hands. It didn't take long for Peter and Tony play with their LEGO set again, this made the Avengers raise an eyebrow. So Tony did have a soft spot for the kid.
Peter turned to glance at the Avengers, he began to speak, "You may not know me now, but we have met before." The rest (except for Tony and Rhodey) began to question what the kid had just said. Peter frowned slightly. "You guys should know me, I'm the spider guy." He turned to Capsicle and said, "I stole your shield remember? I'm the guy that goes pew pew thwip thwip." He made hand gestures as he spoke.
Then it hit them. My dear god, the boy was Spider-Man! They were all surprised. Bucky broke the silence between the group, "Oh my lord, that kid could hold my metal arm, and Steve couldn't even do that!" There was clearly astonishment in his words.
Peter smirked. Tony patted his back and the rest were awestruck. "Are you his father, Tony?" Wanda asked. Tony and Peter glanced at each other for a moment, then turned back to the group. "Well no, um, you see, Mr Stark is a father figure to me, but he isn't my dad." Tony raised his eyebrows. He was quite startled at the response, Peter saw him as a father figure?
Tony grinned to himself. "I actually have the adoption papers," he smirked at Peter, who was jaw dropped with happiness. The rest of the group were calm but in the inside, they were squealing their heads off at the two.
"Congratulations," Steve patted both of their back while Peter and Tony embraced each other with a hug. Why don't we now change Peter Parker to Peter Stark?
{A/N} I want Tony to adopt Peter in the MCU so bad! I just want them to be father and son ⊂( ◜◒◝ )⊃