Peter Parker became Spider-Man in a twist of fate; he attended a lecture that got crashed by a radioactive spider, which bit him. It really could have been anyone there (as canon would later demonstrate by introducing Cindy Moon/Silk, another attendee who also got spider powers). So what if it was someone else?
If it were to be Flash Thompson, he would become a superhero, but because he isn't a science nerd like Peter, he wouldn't invent web shooters. This would become a major problem when he fought Vulture, as unlike Peter, he couldn't catch himself with webslinging and would fall to his death trying to fight the flying supervillain.
If it were to be Betty Brant, she would become the superheroine Spider-Girl with Peter Parker's tech help, and it would actually go pretty well. But when a criminal escapes her and later murders Ben Parker, she would accidentally kill him with her Super-Strength. Unable to cope with having killed someone, Betty would retire.
If it were to be John Jameson, J. Jonah Jameson's astronaut son, his father would, in a rather ironic twist, encourage him to become a superhero. John would become Spider-Jameson, using a jet pack instead of web-shooters. This would come to haunt him during an incident when he has to stop a space capsule falling into Earth's atmosphere. Spider-Man was able to slow its fall by using his webs as a parachute, but Jameson had to rely on his jetpack, which didn't have enough force. John Jameson would save the astronauts, but at the cost of being crushed underneath the capsule when it landed.
In all cases, after the heroes died or retired, Peter Parker would be inspired to reverse-engineer the spider's venom into a Super Serum, and use it on himself to become Spider-Man.
What If... Someone Else Besides This Troper Had Been Bitten By A Radioactive Trope Page?
- Alternate Universe Reed Richards Is Awesome: An inverted version applies to Flash and John's spider-identities, as their lack of webbing results in their deaths compared to Peter being smart enough to devise his webbing and use his mind to solve problems.
- Heroic Sacrifice: John Jameson makes one to save several astronauts from their capsule's unplanned re-entry.
- In Spite of a Nail: In all cases, Peter ends up as Spider-Man anyway. The moral of the story? Even if the spider-bite was chance, Peter was the only one who could have became Spider-Man after being bitten; Flash and Jameson both die because they lack webshooters, and Betty Brant doesn't have the mental fortitude to deal with failure and accidentally killing someone.
- My God, What Have I Done?: Betty basically quits as Spider-Girl because she failed to save Ben Parker and then killed Ben's murderer by accident.
