Amidst all the controversy with the Ant-Man film that was released this year, I think everyone can agree that Marvel Studios was able to pull out a solid effort with the movie, despite having to find a new director and re-write the script to a degree. Scott Lang has proven himself to be a worthwhile addition to the Marvel Cinematic Universe, so much so that we'll see him return in 2018 in the sequel dubbed, "Ant Man and the Wasp". It will be a welcome return for Paul Rudd, Evangeline Lilly, and Michael Douglas but before this movie drops, Lang will return to the big screens in next year's Captain America: Civil War. Civil War was even hinted at in the post credit scene of Ant Man with Steve Roger and Sam Wilson capturing Bucky, ready to give Lang a call to assist them with what was going down.
While Lang has certainly shrunk enough during his time in the MCU, we have yet to see his other alter ego emerge as the growing super hero called, "Giant Man". As we saw in the original Ant-Man movie, Lang also had the ability to grow objects as well as shrink them though we never saw him employ the former on himself. We saw Thomas the Tank Engine grow to epic proportions, smashing through a house, along with an ant grow to the size of a dog, which Lang's daughter now keeps as a pet. With this card up his sleeve, what better time than the dire scenario established in Civil War for him to start using his ability to get several sizes larger?
At the end of the day, Captain America's side of the battle for the Registration Act needs some big guns. On Tony Stark's side, he has Black Panther, the Vision, War Machine, Black Widow, and himself to battle the forces of the Anti-Registration side. While Cap's team is powerful in the form of himself, Hawkeye, Scarlet Witch, Falcon, Bucky and Ant-Man, they seem to be in a completely lower league than Team Stark. With the odds stacked against them, now would be the best time for Scott to gain a few stories of height to start swatting Team Tony's flyers out of the sky. I mean, the Vision alone could arguably beat the anti-registration side with the Mind Gem powering him up.
Captain America: Civil War has a LOT of heroes and each one is going to need their own moment to shine, and considering Ant-Man seems to be one of the weaker members of the team, becoming Giant Man would be a show stopping event for the character. The guy has to be in a movie where we're getting introduced to Black Panther and the Marvel Cinematic Universe version of Spider-Man, he's going to need a serious breakout moment of his own. Aside from obtaining a new alter ego, we can hopefully keep our fingers crossed that we'll also see Ant-Man riding on an arrow shot by Hawkeye at some point because you'd be hard pressed to find a cooler moment in Avengers history, let's be honest.