Peter Parker/ Spider-Man

[It's mostly the same as the Ultimate Spiderman one, but with a little adjustment so it makes sense in the current movie MCU. A friend of mine wrote it, so if you borrow it please give 'dyir' credit.]

Peter Parker, like many kids of his age, think that the Avengers are the coolest thing ever. But for him, he idolizes Iron Man. Tony is a man whose parents are dead, who is very intelligent, and likes to make weird technological inventions. Peter (in canon) was at the Stark Expo in Iron Man 2 because he dreamed of someday being like Iron Man. In the not too distant past from the movies, he attended a science experiment involving high energy particle bombardment, funded by Stark Industries. It malfunctioned, irradiating a harmless spider with the same cosmic ray nonsense that powered the Teserat. Nobody noticed this, but it escaped from the containment room when the experiment malfunctioned, biting Peter as it died of extreme radiation poisoning.

He was bitten, gained superpowers, but doesn't immediately think that doing so makes him a superhero. He still thinks that his path in life is science and being like Iron Man. But money is super tight at home and he can't afford to buy the tools necessary to make cool technology. But now he's super strong and super agile, and Ned is a super nerd for Pro Wrestling. So Ned makes him go see an amateur wrestling match, and the promoter boasts that if anyone can beat the local champion, they'll win a few thousand bucks. Peter is like "dude, that's like free money now that I've got spider powers" and still wants his tools, so he makes a dumb costume. He shows up in costume at the next match as the Amazing Spider-man, beats the local champion, and goes to collect his winnings. The promoter only gives him half of the money he's owed, since Peter won't commit to further matches or reveal his actual name. Peter gets really mad but leaves... and that's when the promoter gets robbed by a local hoodlum. Peter is still really mad at the promoter, so he just lets it happen. When the promoter confronts him afterward, Peter remarks that he might have stepped in if he hadn't been stiffed.

Peter goes to find Uncle Ben, who he'd lied to about where he was, only to find out that Ben had been carjacked by that robber. Ben was shot in the encounter and died at the scene. Peter hurries after the carjacker and when he corners him, he realizes it’s the robber. He's plagued by guilt- if only he hadn't been a dick, hadn't lied to Uncle Ben, hadn't been so focused on the money, if only he'd been a real hero like his idols- then his Uncle Ben would be still alive. This motivates him to start trying to be a masked crime fighter and eventually Tony Stark finds out about him.. and cue Civil War.