Superhero origins haven't always been as important as they are in the age of the MCU, and Marvel's equivalent to the superfast Flash - Robert Frank, the unfortunately named Whizzer - boasts one of the weirdest ever committed to comics. Most famous to MCU fans for a cameo appearance in Netflix's Jessica Jones, played by Jay Klaitz, the Whizzer is a hero from the 'Golden Age' of comics - a time before interconnectivity and continuity were such pressing concerns for comic fans.
Despite this, Whizzer has remained a presence in Marvel Comics. Countless time travel stories have flashed back to Whizzer's time on the wartime Invaders team alongside Captain America, and he was even revealed to be the father of Quicksilver and the Scarlet Witch prior to numerous retcons regarding their parentage. Introduced in USA Comics #1 by Al Avison and a writer whose identity has sadly been lost to time, Robert "Bob" Frank acts as an assistant to his doctor father when the two are framed for murder and forced to leave the country. The framing itself is a truly strange event, but nothing about Whizzer's origin is weirder than the source of his powers.
USA Comics #1 begins with Bob near death from a fever. Bob's father performs a blood transfusion, but is unable to obtain an adequate supply to help Bob recover. The doctor's plight is interrupted when a snake rears back to attack Bob, who is only saved by a mongoose which attacks the serpent, outfoxing the predator with its superior speed. Seeing that the mongoose is wounded, Bob's father has a brainwave, taking blood from the animal and injecting it into Bob before dying from the strain of the experience.
A lot of moments from this sequence are funny to a modern eye. First, that the direct infusion of mongoose blood lacks any mysterious sci-fi element to help it withstand the test of time, like the mysterious vapors or chemicals that created different versions of DC's Flash, and second that Bob instantly gains superspeed. Less glaringly, there's the fact that Bob's father apparently knows this will be the case, telling Bob, "You're going to be different to other men, son -- you have the blood of a mongoose -- the world's fastest animal -- in you. You're going to be a regular whizzer," before collapsing.
In these early days of what would become the Marvel Universe, it is apparently known to science that mongoose blood grants superspeed, and yet Whizzer is still able to return home and become a hero with powers that are effectively unique. Small details add to the strange story, such as Bob's father seemingly only realizing the mongoose has the blood he needs because he sees it's wounded, and mobster Granno tricking the doctor into trying to save his victim just so he can nudge him during the operation and then threaten to say he killed the man on purpose unless he leaves the country.
Later stories would add new details to Whizzer's origin in an attempt to downplay the importance of the mongoose blood, insisting that the transfusion merely triggered his pre-existing mutant potential. Interestingly, Whizzer's origin contains elements that are now iconic to other heroes - like Spider-Man, Whizzer's powers come from taking on the properties of an animal through his blood, and like Captain America, he's depicted as a thin, sickly man turned into a superhuman through medical experimentation. Unlike other heroes from the same era, Whizzer is rarely seen in modern comics, his unfortunate name making him harder to update than some of his contemporaries. Still, Marvel's equivalent to the Flash is no forgotten hero, and his origin - strange as it is - was part of an early testing ground of ideas that would lead to countless iconic heroes, even if Whizzer isn't among them.