The blockbuster films of Batman, Spider-Man, and Superman have cemented these characters' origins in the minds of audiences around the globe. At this point, multiple radioactive spiders have already bitten multiple cinematic Peter Parkers. Many more Marvel heroes have had their stories adapted to the silver screen, but one can always count on comic book continuity to be more complicated than that of a mainstream movie franchise. This has led to several Marvel origins being watered down before hitting the big screen - with some being downright sanitized.
Though some of the Marvel heroes' origins portrayed in the movies have been pretty horrifying, they pale in comparison to what their comic book counterparts had to go through to obtain their superpowers. Casual fans may be surprised to learn that their favorite cinematic protagonists have suffered some of the most harrowing experiences to ever hit the four-color page - adding a whole new perspective to "Whatever It Takes."
What Happens In The Comic: Scott Lang’s origin as the second Ant-Man is very similar to his adventures in the Marvel Cinematic Universe - albeit with an extra degree of tragedy. In the comics, Lang takes up a nefarious lifestyle in order to earn enough cash for his daughter to receive a necessary heart surgery. He then takes the Ant-Man suit from Hank Pym when Cassie’s doctor is abducted by a supervillain. Touched by Lang’s fatherly love, Pym eventually allows him to take over the mantle.
What You See In The Movie: The MCU version of Lang sort of falls *ss-backward into the role of Ant-Man. He’s personally selected by Pym for the job and tricked into taking the suit from Pym’s mansion. Fortunately, there’s no sign of his daughter having a congenital heart condition in film continuity - which might be a bit much for audiences to handle, given Cassie’s undeniable cuteness.
What Happens In The Comic: Rocket has one of the most existentially disturbing origins in all of comics. He starts life out as a therapy animal on a planet-sized insane asylum run by robots, and it only gets stranger from there. When the robot wards gain sentience, they abandon their patients and leave them in the care of Rocket and his fellow pets - but not before subjecting the animals to horrible genetic experiments to equip them for the task. After a fight or two, Rocket escapes Halfworld for a life among the stars.
What You See In The Movie: The Marvel Cinematic Universe doesn’t delve too deeply into Rocket’s backstory, other than suggesting he’s the result of some sort of cybernetic experimentation and “didn’t ask to be made!” There’s no talk of sentient robots or asylum patients, and perhaps that’s for the best.
What Happens In The Comic: Scott Summers has a relatively ordinary childhood - until a family trip is interrupted by an alien attack. While his father is flying them home in a private plane, the family is intercepted by the diabolical Shi’ar. The aliens take Scott's parents while he and his brother Alex have to jump out with the plane’s only parachute. When they hit the ground, Scott suffers head trauma that renders him unable to control his mutant powers later in life. The Summers boys are raised in separate orphanages until Scott’s mutation draws the attention of Charles Xavier.
What You See In The Movie: There have been a couple cinematic versions of Cyclops, but they don't go into much detail on his origin. Basically, Scott Summers develops mutant powers, meets Professor X, and joins the X-Men. There’s no alien plane abductions or traumatic brain trauma involved whatsoever.
What Happens In The Comic: Clint Barton has a tough go of things early on in life. After he and his brother Barney flee their unsafe home, they end up joining a circus. There, the brothers are trained by a future supervillain in the ways of the bow, until some dubious ethical practices at the circus lead Clint to set out on his own. After accidentally dabbling in supervillainy himself, Hawkeye just shows up at Avengers Mansion one day demanding a spot on the team - and he gets it!
What You See In The Movie: There really isn’t much to Hawkeye’s backstory in the Marvel Cinematic Universe. He’s just a highly-trained S.H.I.E.L.D. agent who prefers to use a bow and arrows (and has the implicit trust of Nick Fury). One stint of Loki’s mind-control later and he’s a full-fledged Avenger.