Source: marvel.com
3. Original Sin
The Original Story: Oh, jeez, there’s a bunch of these. Essentially, the basic concept of Original Sin was that, as a result of an incident, a ton of hidden secrets about Marvel Universe characters were revealed to both audience and reader. So the original stories were numerous. Here are a few.
Tony Stark and Bruce Banner had nothing to do with each other before they both became Avengers. Dr. Doom's accident was entirely his fault. Angela came from some sort of generic heavenly dimension. Dum Dum Dugan survived World War II, and was still alive. Peter Parker was the only one bitten by the radioactive spider. Deadpool's parents died mysteriously. And so on and so forth.
The Retcon: In order, I believe it’s like this: Tony Stark tampered with the Gama bomb, and it turned Banner into the Hulk, whereas it previously would have accidentally killed him. Dr. Doom's accident may have been due to Ben Grimm tampering with his hell-viewer device. Angela is Thor's sister. Dum Dum is an LMD. Cindy "Silk" Moon was also bitten, and gained Spider Powers. Deadpool killed his own parents under Weapon X mind control.
Woof. That was a lot, and I didn't even cover Guardians of the Galaxy, X-Men, or Daredevil.
