Bill Skarsgård Has Given Co-Stars More Than A Few Nightmares

International assassin John Wick is one of the fiercest fighters in all of cinema, and that means he needs equally powerful enemies to challenge him. In the latest installment in the franchise, "John Wick: Chapter 4," in theaters now, the titular assassin, played by Keanu Reeves, will face off against his most fearsome foe yet: the Marquis, a vicious bureaucrat who wields red tape like Wick wields his fists.

The Marquis is like the world's most menacing middle manager, a part of the powerful hierarchy of the High Table that control the world of assassins and maintain order in the franchise. Wick hasn't been on good terms with the High Table since "John Wick: Chapter 2," so that means that he and the Marquis have a serious conflict of interest.

Who better to play this corporate creep than one of the freakiest thespians to hit the silver screen in years: Bill Skarsgård. The actor's biggest claim to fame is playing Pennywise the dancing clown in Andy Muschietti's "It" films, where he notoriously terrified co-star Bill Hader with his ability to move his pupils in opposite directions.

That's not the first (or only) time that the Swedish actor has freaked out his co-stars, however, which makes his turn as the malevolent Marquis that much more fun. Skarsgård's various villainous characters over the years have all been pretty wildly different, but the fabulously dressed, French-accented Marquis might truly be the most terrifying of them all.

If anyone knows villains, it's veteran actor Ian McShane, who stars in the "John Wick" franchise as Winston, the manager of the New York Continental Hotel, a neutral territory where assassins can rest and receive their next assignments. In an interview with Screenrant and fellow co-star, the late Lance Reddick, McShane joked about how some of the Marquis' menace came directly from the man who plays him:

"He's six foot five, he [wears] appalling suits, he's Swedish, and he speaks nineteen languages. And he's one Skarsgård and he's got 1,000 brothers. No, I love Bill. I think Bill is great in the [movie], crazy as a loon."

Easy jokes about the sheer number of Skarsgårds aside, having McShane call your performance "crazy as a loon" is a pretty serious compliment. McShane seems pretty nonplussed about the whole thing, but maybe the star of the action sequel has had enough experience playing pretend in the world of international assassins to not bat an eye at the actor's ability to be seriously scary. Other co-stars who have acted alongside Bill Skarsgård haven't been quite as hardened to his spooky skills, however, because he's managed to freak out more than a few of them.

Pennywise from "It" is one of horror's most frightening villains, and Bill Skarsgård portrayed him perfectly in Andy Muschietti's film adaptations of the novel by Stephen King. He's a shapeshifting extraterrestrial entity who takes the form of people's nightmares, most specifically in the shape of a creepy killer clown. While the actor seems perfectly pleasant in interviews, many of his co-stars in the two films were unsettled just by sharing a set.

On "Good Morning America" (via BloodyDisgusting), "It Chapter Two" co-star James McAvoy shared just how much the actor managed to freak out his fellow thespians:

"He's amazing. [Skarsgård] is terrifying. He's a lovely guy, and yet he really freaked me out. I remember standing there with the rest of the cast, all these adults, and we'd all done weird, freaky stuff. And we are all looking at each other going, 'I don't like being here. I don't like being an actor today.'"

McAvoy went on to admit that he doesn't really like clowns much anyway, but that Skarsgård really freaked him out beyond his old childhood fears. The fact that Hader and McAvoy have starred in all kinds of horrific stuff before, like HBO's "Barry" and the M. Night Shyamalan film "Split," and still found Skarsgård unnerving is genuinely impressive. The Swedish actor's adult co-stars weren't the only ones who found him fearsome, however, as he also terrified the child stars of "It Chapter One."

In an interview with his older brother (and fellow actor) Alexander Skarsgård for Interview magazine, Bill Skarsgård revealed that he really upset at least one of his kiddie co-stars on the set of "It Chapter One" when he first appeared on-set to perform with them:

"At one point, they set up this entire scene, and these kids come in, and none of them have seen me yet. Their parents have brought them in, these little extras, right? And then I come out as Pennywise, and these kids — young, normal kids — I saw the reaction that they had. Some of them were really intrigued, but some couldn't look at me, and some were shaking. This one kid started crying. He started to cry and the director yelled, "Action!" And when they say "action," I am completely in character. So some of these kids got terrified and started to cry in the middle of the take, and then I realized, "Holy s***. What am I doing? What is this? This is horrible."

That sounds like a bit from a Nathan Fielder show, but it really happened, and both the actor and children were scarred a bit by the experience. Thankfully, not all of the child actors in the film were bothered by his performance. For example, Jack Dylan Grazer, who plays Loser's Club member Eddie and ends up trapped beneath a screaming, drooling Pennywise, would just compliment Skarsgård on his acting as soon as he heard "cut!"

Playing Pennywise helped launch Skarsgård to serious stardom, but it also had a lingering legacy when he took on other roles, and that meant scaring yet more co-stars.

Playing Pennywise has stuck with Bill Skarsgård even though the movies themselves are over. There are subtle indicators, like casting him as a fairly non-threatening guy in a very threatening position in the horror film "Barbarian," and then there are the co-stars who lose their minds when they learn that they're performing with Pennywise.

In an interview with Rian Johnson for Interview Magazine, "The Devil All the Time" director Antonio Campos revealed that young actor Michael Banks Repeta reacted pretty strongly to finding out his co-star had played the dancing clown. Apparently, Campos went over a scary scene with Repeta and his mother when he learned that the only thing Banks was afraid of was — you guessed it — Pennywise. Shocked, Campos told Skarsgård not to say anything to the young actor, who hadn't pieced together the fact without the white clown makeup and creepy grin. Campos explained:

"And Bill is like, 'Oh my god. I'm totally going to tell him.' So the day that we were shooting that scene, Bill was like, 'They don't think you can know this, but I know you're a smart kid. I'm the clown in 'It.” And Banks was like, 'Whoa, that's crazy. I didn't know that. Alright.' And I don't know if this is connected, but in the middle of that scene Banks just burst into tears way before he was supposed to. I think that somehow really got to him."

Whether he's making children cry or scaring the living daylights out of his adult co-stars, Bill Skarsgård is great at being truly terrifying. Here's hoping the Marquis doesn't end up invading our nightmares too!