"It's not a heist… it's a demolition!"

Except it's totally a heist, even if a costumed-up Scott Lang is shouting to the contrary, in the midst of a big beat-'em-up battle against Darren Cross. Well, "big" in the "Ant-Man" sense of the word, at least. In the context of the new Marvel Studios superhero movie, "big" means something closer to "small," but still packs one hell of a punch.

I'm learning this new definition firsthand on the Atlanta set of "Ant-Man," watching Paul Rudd and Corey Stoll shoot a climactic battle and argument on a helicopter, trading verbal barbs as bullets fly at our hero, bouncing around evading the gunfire. Director Peyton Reed, now firmly entrenched in the movie after all the preceding Edgar Wright drama, dutifully keeps the scene rolling along, take after take, while I watch on a monitor alongside a handful of fellow journalists.

We're so caught up in the action, trying to piece together how a heist movie like "Ant-Man" isn't a heist, but "a demolition," in Lang's words, that we're all caught off guard when Lang himself walks through the door.

Behold: Ant-Man. Paul Rudd struts into the journalist holding area fully armored up, the leather of the Ant-Man costume clinging to his hard-earned Marvel movie muscles, his signature smirk pasted on his face for all to see, thanks to his helmet's visor being lifted above his eyebrows. It's a surreal sight for everyone in the room, even Rudd at this point in filming.

"I love it," he says of the costume, even while acknowledging the difficulty of wearing the thing, what with the fact that it consists of 400 unique components. It's October, and Rudd's already forecasting the following year's Halloween plans with his kids: "The three of us are going as Ant-Man, changing sizes."

Rudd sees big things in the future for Ant-Man, and he's rightfully invested in the character and concept — not just because he's the star strapped inside the suit, but also because he's one of the creative minds responsible for writing Scott Lang and the film's other heroes and villains.

"It was obviously never part of the plan, when Edgar and Marvel parted ways," he says of his involvement in writing the script, alongside "Anchorman" director and frequent collaborator Adam McKay. "It's a constant work in progress."

Having witnessed that work firsthand, here's what I can tell you about how Rudd and the Marvel team are progressing on "Ant-Man":

Why Ant-Man?

That's the question on everyone's mind, isn't it? Even the movie's marketing is leaning on Avengers like Iron Man to point out that Ant-Man is a figure worth taking seriously on his own, and yet, there are still fans wondering about the size-changing hero.

The reasons are many, according to Kevin Feige, the Marvel Studios executive producer responsible for overseeing one of the most complicated big-budget franchises in movie history. Chalk it up to "expanding the cinematic mythology" of the Marvel Universe, or reminding fans that Marvel's universe is "big" with roots dating back to the Howard Stark and Peggy Carter era of so many decades ago. But there's a simpler reason for Feige: Crossing another big name off the Avengers bucket list.

"He's an Avenger," says Feige. "He and Wasp are on the cover of that first issue of 'Avengers.' I don't know if they're around here, but in the offices at Disney, we have big blow-ups of 'Avengers' #1, and I just love the fact that each of those characters are finally coming to life — and two more will be heading there in this movie."

Yes, Wasp

Before moving any further, don't worry about drilling too deep into Feige's "two more" comment. He outright confirms that Wasp, a founding Avenger in the comics, has a role to play in "Ant-Man," albeit an unexpected one.

"She factors in a number of spoiler-ish ways," he says, choosing his words carefully. "But we will see Janet van Dyne in action in this film, and sort of what happened to her."

The Pym Problem

What happened to Janet van Dyne? Feige and the team won't say much, except that whatever happened wasn't very good, leading to Cold War era hero Hank Pym hanging up his Ant-Man suit once and for all, and leading to a rift between Hank and his daughter, Hope.

"Hope and her father don't get along very well," says Evangeline Lilly, who plays Pym's daughter. "And they haven't for many years, for most of her life."

But circumstances force Hank and Hope to cast aside their differences, thanks to a mutual person in their lives…

Cross The Streams

Corey Stoll of "The Strain" and "House of Cards" plays scientist and businessman Darren Cross, the chief antagonist in the movie. Once upon a time, he was Hank Pym's protege. Now, he's using the so-called "Pym particles" for his own financial benefit, designing technology that Hank deems dangerous.

"There's a dark side to Hank," says Michael Douglas, "and it makes him understand where someone like Darren can go, and where he's going to go. He feels guilty for evolving and developing this [technology] and seeing how it can be used in a negative fashion."

Hank's plan to thwart Darren involves a heist, requiring assistance from Hope, who works with Cross, and another individual — the same individual standing front and center in all the "Ant-Man" movie posters.

An All-New Ant-Man

Paul Rudd plays small-time crook and thief Scott Lang, a man who is more than familiar with the revolving door of the prison system. He's down on his luck when we meet him, both professionally and especially personally, what with his ex-wife remarried to a cop, and his visits with his own daughter few and far between.

"We meet him as he's leaving prison," says Feige. "We figure he's been in for four or five years. His daughter is six. He doesn't have much of a relationship with her, and he very much wants a relationship with her, but he can't hold down a job, and he can't pay child support."

Scott's solution to his problem? Becoming part of Hank Pym's problems. Pym needs a thief with a particular set of skills, and Scott is the man with those skills. So Hank hands him his old Ant-Man costume, and an all-new Ant-Man is born.

An All-New Director

Life imitated art in the case of "Ant-Man," in the sense that a creative shakeup necessitated a new person taking the wheel on the film. Edgar Wright, long associated with "Ant-Man" from even before the launch of "Iron Man," walked away from the project with weeks to go before filming began. A long search for a new director commenced, leading to some panic along the way for Marvel and the entire "Ant-Man" team they assembled, including Rudd, Douglas, Lilly and the rest of the cast.

"The concern or panic was that we weren't making the movie we all wanted to make together," says Feige. "That's where the panic set in. That we were heading toward something that none of us would be pleased with."

In a way, he says, Wright's departure was "a relief that we weren't going to make a big mistake together." It also paved the way for Peyton Reed, someone Feige once worked with on an early version of "Fantastic Four" at Fox.

"He's one of the first filmmakers that I really spent a lot of time with, and spent a lot of time developing a script with," says Feige. "Thankfully, when Peyton came in, he jumped in with both feet and with great confidence, and that's led us to this point."

"I was understandably upset when Edgar left," says Rudd, "but I was also excited when Peyton came aboard. He's somebody that knows and loves the source material and understands the world, and is open to new ideas and trying different things."

An All-New Writing Team

It's important that Reed and Rudd have a solid working relationship with one another, given Rudd's starring role in "Ant-Man," as well as his other key responsibility: writing the thing.

Indeed, Wright wasn't just the original "Ant-Man" director, but also one of the original writers, alongside Joe Cornish. The bones of their story remain very much intact, according to everyone involved, but the new vision of the post-Wright era required new writing voices as well: McKay and Rudd, who have a strong working history together from their "Anchorman" days.

"It's a fairly sizable rewrite," says Rudd, "but the tone of what we were trying to write and what we were doing is not a comedy, per se. It fits more in line with what people have come to expect from these films."

"But there are moments of levity," he adds, laughing. "We are dealing with ants here, after all."

The Ants Go Marching

Indeed, the human heroes have a huge role to play in "Ant-Man," but what about the inhuman ones? Not capital-i Inhuman, mind you, but the ants that Scott Lang can control and communicate with thanks to Hank Pym's technology.

"You are going to see more ants than you probably want to see," laughs Feige. "It's not dissimilar to the way I would talk about Rocket and Groot [from 'Guardians of the Galaxy']. There were some people that inherently understood that a talking raccoon with a machine gun is just cool. A lot of people did not. A lot of people went, 'So, what, it's a raccoon? It's a tree?' And I would say, 'Yes, and you'll laugh at the tree at the beginning, but by the end you're really going to feel for the tree.'"

Feige and the team are hoping for something similar here with the ants in "Ant-Man," whether it's a small army of the insects working inside of Hank Pym's San Francisco home, or the flying ants that will help Scott out during the helicopter sequence we witnessed earlier in the day, or one particular ant that Scott may or may not refer to as "Antony."

"There are so many different kinds of ant species, and we're going to see a good half dozen or dozen of them in this," says Feige. "Hopefully you'll be cheering for them, or you'll get upset if one or two or three get blown away by the bad guy."

The New Big

Given the hero's size-shrinking super-powers, "Ant-Man" plays in a smaller sandbox than the preceding Marvel movies. Its major action set pieces involve Scott slugging it out with Yellowjacket (the size-changing alter ego and suit Cross develops for himself using Pym particles) inside of a brief case, and in his own daughter's bed room. There are no falling S.H.I.E.L.D. helicarriers in here, but there are plenty of high-flying moments with Ant-Man — albeit on ant-back.

Small becomes big in the case of "Ant-Man," in other words, thanks in large to a macro photography team that lenses craps tables, ATMs and other real-life objects, which will all be used as actual backdrops featured in the movie.

"We're putting him into these actual environments," says Feige, "so there's a lot of unique processes that we're using to gather all this stuff."

Staying Grounded

The other component of a blown-up smaller-scale superhero movie, says Rudd, is finding a way to realistically interpret Scott Lang's power set, and to get into the mind of his situation. It's easier said than done, especially for Rudd, who is far from a rookie at this stage of his career, but is still very new to the whole action movie hero situation.

"At its core, it's just believing in the situation nd throwing yourself into it whole heartedly and trying not to be self conscious," he says of how he gets inside the character of Ant-Man. "Today, I'm hanging out of a helicopter and pretending that I'm flapping around, and then there are ants holding onto seat belts, and… you know, out of context, it's just ridiculous!"

"But it's also the kind of thing we all did when we were five years old and playing in our living rooms," he adds, still proudly sporting his Ant-Man gear. "We all believed it when we were kids. It's just holding onto that, I guess."

What's Next?

Well, for one thing, the movie has to come out. "Ant-Man" hits theaters on July 17, still several weeks away, in the middle of one of the busiest summers in recent Hollywood history. It also comes on the heels of "Avengers: Age of Ultron," one of the biggest movies of the year, what with its $1.3 billion and climbing haul across the world. No pressure here, Mr. Lang!

But regardless of how he performs in his solo debut, there's already more Ant-Man in both Marvel and Rudd's futures. Although we didn't know it at the time of the visit, Marvel has already tasked Rudd with bringing Scott Lang into the greater Marvel Cinematic Universe, with a co-starring role in "Captain America: Civil War." What will Ant-Man look like when he's standing alongside the Avengers? Hopefully, for Feige, it'll look as natural as that "Avengers" #1 cover. For Rudd, it'll be surreal, to put it in a word.

"I was just in the same room with them at Comic-Con," he says, "and I was a wallflower. I just felt like I was walking around with the Beatles."

The proverbial Beatles now have an Ant to add to their roster, and we'll see a preview of how they'll all get along when Rudd makes his superhero movie debut in just a few short weeks.