I've been re-watching the TV series "Leverage", but it's disappointing in not believable. It's based in an insane world where the rich and powerful can eventually lose their money and go to jail.

Thanks for the explainer!

OK, so I have the 2009 edition of the Marvel Encyclopedia, which has 8 pages devoted to The Hulk. Apparently he had "every atom of his body exposed to gamma radiation" from a gamma-bomb he was working on. It's been revealed that Banner also has multiple personality disorder that contributes to his various Hulk forms.

I thought I remember from decades ago that his bulk and healing energy comes and goes from a transdimensional space, but I can't seem to find that in the article.

However, I really like this StackExchange answer, which posits that he is an energy-processing mutant that taps into the Power Cosmic to fuel his incredible strength. https://scifi.stackexchange.com/a/84410

Also, we won't get cheap eggs and gas.

"Pre-existing conditions" is just insurance industry slang for something we all have: "medical history".