So here's the Uncle Ben comic strip. His death may be different from different incarnations, especially the events leading up to it. But I'll try my best to explain.

If we're talking My hero Academia style, then this takes place within the 10 month time period where Deku trains with All Might to be able to stand the power of One for All, only here, Peter uses this time to hone his powers under the guidance of Stark. He starts getting overconfident with his powers and starts doing vigilante stuff, saying that the people who need help cannot wait for him to graduate and be a Pro Hero...they need help whenever they need it in that instant. For a week, he tails this shifty character named Tombstone. And one night, just as he leaves to follow Tombstone to his base, he and Ben have a fight, with Ben being unsupportive of this vigilante thing Peter's got going. Peter dismisses this and leaves anyway. Ben calls Stark and tells him that Peter is planning on taking on this Tombstone guy, to which Stark immediately tells him to not engage and wait for help. Ben follows the webs that Peter leaves behind from swinging and ends up in an abandoned warehouse. He waits a few minutes but no hero has come. He hears crashes and screams. 

Peter is in trouble...

He goes in and takes out the thug who was beating on Peter. He finds out that Peter's wrists have started to bruise and strain from his overusage of the webs. Many more come in and waiting was no longer an option. 

So yeah, basically that's how Ben dies in my AU. Might be the cringiest, but I had a lot of fun doing this. If you've got any ideas on how you would make Ben die (that sounds...harsh really...I'm sorry), lemme know in the comments. If you've got any commission requests, holler at me on Notes. 

Note: My Marvel Academia is a fan AU of two pre-existing universes: Marvel, and My Hero Academia. This is a mere crossover.