Paul Rudd became an Avenger and remained Paul Rudd

He imparts this knowledge as if he has been carrying it around for years. Maybe an above-average understanding of insect life is just a function of playing Ant-Man, the Marvel superhero whose suit allows him to shrink all the way down to subatomic size. Later that January evening, a stranger at the museum catches a glimpse of the 53-year-old actor and exclaims, “Don’t sting me!” Rudd smiles politely. He has become the ant.

The encounter doesn’t faze Rudd, who has spent nearly a decade in the Marvel Cinematic Universe, leading three of its stand-alone films — the latest, “Ant-Man and the Wasp: Quantumania,” out Friday.

He was already a star before, securing heartthrob status in 1995’s “Clueless” and displaying affable goofiness in some of the aughts’ biggest studio comedies, including “Anchorman: The Legend of Ron Burgundy” and “The 40-Year-Old Virgin.” Playing Ant-Man thrust Rudd in front of a devout global audience. His list of credits now boasts the second-highest-grossing film of all time.

To Rudd, the Marvel projects are similar to any other: He stands in front of a camera trying to remember his lines and hit his mark, same as he would on the set of a Judd Apatow movie. Sure, he helped save the world a few times. He’s still Paul Rudd.

“I thought if I were ever going to be cast as a superhero, something like ‘Ant-Man’ would make sense,” he says. “This is not someone who’s really born with any kind of superhuman ability. He’s just a regular person.”

People claim Rudd doesn’t age. His boyish looks are the stuff of legend, the one superpower he really does possess. Jason Segel, who acted with Rudd in “Forgetting Sarah Marshall” and “I Love You, Man,” says his former co-star is “tirelessly handsome to the point that he may be a vampire. It’s like he got bit during his prime.”

Rudd doesn’t always feel so frozen in time. At an Italian restaurant near the museum, he laments needing to put on a pair of glasses to read the menu when he’s already wearing contact lenses. He can no longer drink as much coffee as he used to, and even red wine disrupts his sleep these days. He orders a glass of pinot noir anyway.

After shooting Season 3 of Hulu’s “Only Murders in the Building” this week, Rudd is set to hop on a plane tomorrow to Kansas City, where he’ll attend the AFC championship game in support of the Chiefs, his hometown team. (They’ll end up winning the Super Bowl, a good time for Rudd.) He was born in New Jersey but moved to Kansas with his family when he was 10 for his father’s job with the now-defunct Trans World Airlines. It wasn’t the coolest place to live, but that shaped him. “It puts people in their place,” he says.

Not that Rudd had much of an ego to check. “I felt a little bit like an outsider because I was always the new kid in school,” he says. “Your world is your world when you’re little.” Even after his family settled, he stood out as a Jewish kid in Kansas with English parents. “I realized at a young age that if I ever made Jewish jokes, that got really big laughs.” What he didn’t realize until later is that his peers weren’t always laughing with him.

This could have been Rudd’s villain origin story, but instead it made him more empathetic. He strives to understand the people he meets and has concluded that, for the most part, we all just want to feel fulfilled.

He approaches acting the same way. Segel says while he and Rudd bonded over their “potentially juvenile sense of humor,” they also share an aversion to jokes at someone else’s expense. He recalls the silly scene from 2008’s “Forgetting Sarah Marshall” in which Rudd teaches Segel’s character to surf — or tries, anyway. When Segel gets up on the board, Rudd tells him to “do less.” When Segel does nothing, Rudd demands he “do more than that.”

Frustration builds as they go back and forth for a while in the scene they mostly improvised, which can be risky in the wrong company. But Rudd noticed and bounced off even the smallest choices Segel made.

“If the ship was going down, we were going down together. It was a really joyful collaboration,” Segel says. “When something is going well with an actor currently, I think to myself, ‘Gosh, it’s like when I was acting with Rudd.’”

Amy Poehler was struck by his “giant sense of play” when they first worked together, on 2001’s “Wet Hot American Summer,” in which they, as adults, played teen camp counselors. He moped around as the film’s resident bad boy and years later played a different brand of man-child while guest-starring as city council candidate Bobby Newport in “Parks and Recreation,” the NBC sitcom Poehler starred in for seven seasons.

“We’ve done a lot of dumb stuff together,” she says. “The thing I remember most is the laughs … a lot of fun, joyous, irreverent times. There’s a lightness Paul has that draws a lot of people to him. I think in a time when things can get really, really heavy, there’s something about the way he looks at the world. It’s nice to be around.”

Maybe that’s the secret to his youthful glow.

When Rudd tells people he’s from Kansas, they often bring up “The Wizard of Oz” as a reference point. Peyton Reed, who directed all three Ant-Man movies, goes a couple degrees further: In a way, Rudd is Dorothy.

Reed is talking about “Quantumania,” the latest movie in which Rudd’s character — Scott Lang, a petty thief before he became Ant-Man — dives deep into the Quantum Realm, a minuscule dimension that defies the laws of physics in unpredictable ways. By this point in the series, Scott operates as a trusted “gateway person” into unfamiliar territory. He carries the audience through this subatomic Land of Oz.

Much of the anticipation for “Quantumania” is directed not toward ol’ Ant-Man but instead the introduction of Kang the Conqueror, a formidable time-traveling antagonist played by Jonathan Majors. With the good guys growing in number, too — Marvel newcomer Kathryn Newton plays Scott’s 18-year-old daughter Cassie, joining returning actors Michael Douglas, Evangeline Lilly and Michelle Pfeiffer — Rudd now acts in an ensemble.

Some leads would hesitate to cede the spotlight or give up punchlines. But Rudd isn’t precious with material. He knows nothing is ever set in stone: “Anchorman” director Adam McKay notes in an email that one of his favorite lines in the 2004 film — “60 percent of the time, it works every time,” about the effectiveness of the stinky “Sex Panther” cologne Rudd’s character proudly wears — was something they tossed around in between takes.

McKay and Rudd teamed up to rewrite the initial “Ant-Man” script, and the actor co-wrote the second film as well. Reed says Rudd plays so well with others while acting because, as a writer, “he knows how to fit everybody in.”

“He’s the host of the party,” the director says. “He’s not an actor who counts lines.”

Rudd might attribute this quality to his background onstage, where he learned how to really listen to other actors. After attending the University of Kansas, he enrolled at the American Academy of Dramatic Arts in Los Angeles and spent time studying Jacobean drama in Oxford, England. He lives in New York for its theater scene and first performed on Broadway in 1997’s “The Last Night of Ballyhoo,” returning over the years to act in plays such as “Twelfth Night” and Richard Greenberg’s “Three Days of Rain.”

Being on Broadway is an enormous feat for any performer, but it also reminded Rudd of his humbling Midwestern youth. Contributing to such a grand tradition makes you feel “not so big for your britches” at times.

“Broadway is bigger than any one show or any one actor. … You feel a part of it, but you don’t feel like the king of it,” he says. “Lin-Manuel [Miranda] might have a different answer. But I actually don’t even think he would.”

Rudd stumbled into a similar position on the behemoth NBC sitcom “Friends,” having signed up for two episodes as Mike Hannigan, love interest to Lisa Kudrow’s Phoebe Buffay. The writers extended his arc — eventually leading to Mike and Phoebe’s wedding — and Rudd appeared in the 2004 series finale. (The “Friends” reunion special from two years ago includes footage of him filming the cast’s final bow on a camcorder.)

He felt a bit like Mike again while filming the big fight scene in 2016’s “Captain America: Civil War,” albeit swapping Monica and Chandler’s apartment for a German airport tarmac. It was Rudd’s first time with the other Avengers. He spotted Anthony Mackie’s Falcon costume hanging in the makeshift dressing room they all shared. He turned to the left, and there stood Sebastian Stan with the Winter Soldier’s metal arm dangling off his body.

At one point, Chris Evans had to run to the bathroom and handed his Captain America shield to a props person. Rudd walked up to the guy and asked to hold it. There he was, hanging out with the superheroes who have come to dominate his industry.

But the illusion wasn’t shattered. “I still am, to this day, caught up in the coolness of that.”

Ant-size ego or not, Rudd is still a movie star. Poehler says he has “main character energy.” His green eyes, which appear slightly magnified through his glasses, still sparkle in the museum’s fluorescent lighting. He is charming as hell, cracking jokes about the entomology collection — no, really — that even make the no-nonsense curator smile.

It turns out Rudd actually did do some insect research while writing those Ant-Man movies. An early draft worked in trap-jaw ants, which can “escape jump” by snapping their jaws against the ground and using the immense force to fling themselves into the air. And when ants travel by water, he says excitedly, they make rafts with their bodies and put their babies on the bottom because they’re more buoyant than the adults. Godspeed to Scott Lang’s daughter.

When Rudd was officially cast as Ant-Man after years of being in talks for the role, skeptics wondered whether he could believably play a superhero. He didn’t doubt his own ability, recalling the intense backlash to Michael Keaton being cast as Batman in the late 1980s. Back then, Rudd thought to himself, “What a great choice. He’s hilarious.”

“I’m not trying to make myself out to be Batman and Michael Keaton,” he quickly clarifies. It’s just that Ant-Man is an inherently goofy Avenger, and high jinks are the name of Rudd’s game. He regales me over dinner with stories from his past, including the time he and his high school buddies made fake IDs for a spring break trip.

They used a typewriter to make state IDs. One friend said he was “5-foot-12.” Another used Wite-Out to fix a mistake. They all printed out Colorado state seals and glued them to the backs. When they finally found some “cheese-ball place, probably in a strip mall in Fort Lauderdale,” they handed their IDs to a bouncer.

“The guy took the IDs and he went, ‘Are you kidding me?’ And then his boss came over,” Rudd says. “He took one of the IDs and goes, ‘Oh, well, it’s got a state seal, so you know it’s legit. These guys are good.’”

The teenagers celebrated their victory. How fortuitous that they remembered to include those seals. It wasn’t until Rudd reached his 40s that he thought back to the situation and realized the boss had been messing with them. His very first acting lesson.

Rudd shakes his head. “It was a simpler time.”