Ever wonder how the Incredible Hulk got so incredible? So did Stanford biologist Sebastian Alvaredo.
As the label "Stanford biologist" would imply, Alvaredo knows a thing or two (or several) about science. He also happens to be a huge comic book nerd, from the looks of it. After all, it would take a real interest in both those topics to create this video explaining the science behind how the heck the Hulk goes from Bruce Banner to the big green guy and back.
So the answer is...hemoglobin? Something? Sorry, we were too busy reading comic books inside our textbooks in biology class to be able to explain what's up with the Hulk. But we did learn a cool new word: biliverdin. Oooooh, science.
As Laughing Squid points out, Alvaredo has also given Captain America the science guy treatment. Somehow, watching these makes us feel very smart and very stupid, all at the same time. Biliverdin!
For all his smarts, there's still one thing Alvaredo can't tell you, though: How the Hulk's pants stay on post-transformation. Sorry, earth. Some things are just meant to stay a mystery.