It started with a refrain of "Come to Brazil." After "Stranger Things" premiered on Netflix in July 2016, a then-13-year-old Finn Wolfhard logged on to Instagram to find he was rapidly going from unknown Canadian kid to one of the most recognizable young actors in the world. As the flood of three-word requests from new South American fans poured in and his follower count skyrocketed, Wolfhard looked on agape.

Netflix's original programming had already been well underway with critically acclaimed dramas like "House of Cards" and "Orange Is the New Black," but the streaming giant hadn't had a global hit that could inspire such a broad and zealous fan base. When Wolfhard filmed the first season in Atlanta, "the show felt really contained," he said during a recent video call from his home in Los Angeles. "It felt like a thing that was big, but also really small."

But, of course, it wasn't small at all.

Five years later, "Stranger Things" remains one of Netflix's most popular shows, with its second and third seasons racking up more than 1 billion combined viewing hours, according to data provided by Netflix. Wolfhard's face can be found on T-shirts, Christmas ornaments and action figures. And his star-making role led to his earning blockbuster parts in the "It" films and "Ghostbusters: Afterlife."

Wolfhard plays the grandson of Egon Spengler in "Afterlife," directed by Jason Reitman, son of the original films' helmer, Ivan Reitman. (Spengler, for those who don't remember, was played by the late Harold Ramis and was the awkward but resourceful inventor in the original Ghostbusters team.) "Afterlife" is set decades after 1989's "Ghostbusters II" and sees Egon's daughter (Carrie Coon) and her two children (Wolfhard and McKenna Grace) inherit Egon's Oklahoma farmhouse and get swept up in their own paranormal adventures in the Ecto-1, which was gathering dust in the barn.

With his gangly 5-foot-11 frame, Wolfhard thought it would be fun to take his character, Trevor, from a "boring older brother" part into a paradigm of physical comedy. "I had come into my body a little more with puberty, and I thought my body was really funny," he said. For Reitman, the way Finn "listens and acts through his limbs reminds me of the great teenage (performances) of the '80s. Ferris Bueller, Marty McFly, Bender," the director said in an email. "Finn is a storyteller at heart. He's looking for every opportunity to convey story, not just the dialogue."

In fact, 18-year-old Wolfhard has grown nearly a foot since his career began. Excellent for comedy, difficult for blending in with a crowd. The Internet is full of dimly lit, heavily zoomed videos and photos shot by fans trailing him down city streets and loitering at the movie theaters and restaurants he patronizes. While filming "Afterlife" in Alberta, Canada — as is the case pretty much anywhere he goes in the world — Wolfhard was routinely approached by fans of all ages who recognized his mop of dark curly hair and unique features as belonging to "the kid from 'Stranger Things.'"

"That is very heavy space to occupy," his co-star Coon said. "As we know, many child stars do not make it. They don't make it in the business, but they also sometimes don't make it in the world because of the pressure. Finn has great parents, and he recognizes that his self-worth is not contingent upon that attention."

Perhaps because of the '80s nostalgia woven throughout his career, it's easy to view Wolfhard through a time-warped lens, to imagine he's actually a world-weary Gen Xer with a decades-long career behind him. But he wasn't even born until 2002, and as a child actor coming of age in the late 2010s, he's grappled with a type of fame completely foreign to those who came before him.

In an age when social media posts are a currency often written into contracts and follower counts can serve as a deciding factor in casting, Wolfhard refuses to get caught up in the hype.

He's amassed more than 20 million Instagram followers but uses his verified account only for the requisite publicity posts because he finds the platform "anxiety-inducing and distracting." Same with TikTok and Twitter, the latter of which he deleted entirely before returning to fulfill contractual promotional obligations for "Afterlife."

"I learned after the fact how many people love him, how huge he is, how many followers he has — things I have no awareness of because I'm a fossil," his "Afterlife" co-star Paul Rudd said. "Working with him, you would never know that. There's nothing pretentious or high and mighty about him. He's just a cool kid."

But the access some fans feel entitled to and the information they're able to dig up online are alarming. Strangers periodically threaten to release Wolfhard's personal data in a bid to get his attention, and recently, someone threatened to expose an address that belonged to his girlfriend unless Wolfhard confirmed their relationship. He complied. "They're like, 'Oh, okay, I'm so sorry. We love her,' " he said. "It all fades literally once you're like, 'Hey, calm down. It's cool. I'm a real person.' It's almost like a trance or something. Maybe it's a power thing."

He wrestles less with the notion of what his life could have been if he wasn't famous and more with why he didn't give himself the space to want typical teenage experiences in the first place. As his fame grew, so did the gulf between him and his "normal" childhood friends. They'd invite him to house parties. He'd instantly decline. They assumed he thought he was too good for them. He was secretly panicking that he'd lose everything with one wrong move.

"In my head, I couldn't let loose in any certain way. I thought that if I would have gone with a friend to a party, my career would have been over," he said. "You're afraid that someone can see you as a 14-year-old at a party with a beer in your hand, and it can all go away. That was my thought."

Instead, at 14, he was dealing with other public issues. In October 2017, the nascent weeks of Hollywood's #MeToo movement, Wolfhard's then-agent Tyler Grasham was accused of sexual misconduct by several other young male actors. Wolfhard swiftly left the agency, making him one of the first clients to take concrete action. That decision, he says now, was an easy one.

"He was abusing his power. When it comes to something like that, you can't be personal, like, 'Yeah, but I've met him and he's really nice.' When something incredibly serious and awful like that comes out, there's no going back," Wolfhard said. "When I found that out, I was like, 'Oh, absolutely fire him. That's insane.' I felt so terrible for the people who were harmed by this person." (Grasham did not respond to an emailed request for comment. Ultimately, no charges were filed against him, and he continues to work in the industry.)

Those who've worked with Wolfhard praise the way he makes it all feel "effortless" and "easy," but in private, he's struggled with anxiety about performing, fame and life in general. Transcendental meditation and Lexapro help, he said, and this year, he found a kindred, anxious spirit in Jesse Eisenberg, who directed him in the upcoming dramedy "When You Finish Saving the World."

"I was really nervous about doing the movie, and Jesse was like, 'Who do you think you're talking to? Have you seen my movies? I'm the most anxious person you've ever seen in your life,'" Wolfhard laughed. Eisenberg shared stories of vomiting in bed before shooting the first "Zombieland" and having a panic attack on the set of "Adventureland," which "kind of made me calm down," Wolfhard said. "The anxiety never goes away, but it's something that becomes way easier to deal with. You need a little bit of anxiety to get out of bed in the morning."