Plenty of superheroes have "scientific" origins - genetic mutation, radioactive spider attacks, and hazardous waste baths, to name just a few. But even though these origin stories take some fantastical and goofy turns, there are basic scientific principles that make them "possible" in their comic book universes. Stanford biologist Sebastian Alvarado comes to the rescue in these two videos, where he shares his theories on the science behind becoming super.

Above, Alvarado dissects Captain America, who in Marvel's film adaptation is injected with a "super soldier serum" and blasted with "Vita-Rays." Since geneticists have already identified many of the genes that relate to muscle mass, it could be that this super serum targets and activates them.

But what about the Vita-Rays? Besides having a delightfully period-appropriate proprietary name, the rays remind Alvarado of certain drugs in development. Photosensitive drug carriers are currently in development, Alvarado said in his video, and they only release their payload when exposed to a certain wavelength of light. Perhaps the gene-editing super serum is designed to work only after a particular light blast.

Alvarado also tackles The Incredible Hulk, which he says takes a bit more creativity. The brilliant Bruce Banner is caught in a gamma ray explosion, and survives with the small side effect of turning into a giant green rage monster on occasion.

But Alvarado's theory, while a bit of a stretch, is pretty fun: Gamma radiation causes tiny breaks in your DNA. A few of these breaks are no big deal. But if a huge number of them happened at once, Alvarado suggests, then maybe the reassembly left things a bit...smashed.

"If there's one mystery though that science just can't solve," Alvarado says in the video, "it's how his pants stay on after every transformation."