WARNING: There are some Stranger Things spoilers below.

You probably don't know Mark Steger's face, but you've likely seen his work. As one of Hollywood's top movement choreographers, the actor and artist has brought a plethora of inhuman creatures to life in such popular films and TV shows as I Am Legend, World War Z, Men in Black II and American Horror Story, to name just a few. This summer, Steger enjoyed perhaps his biggest role to date as the the petal-headed Monster in Netflix's breakout hit Stranger Things, the Duffer Brothers-created series that has become a bona fide phenomenon since premiering in July. A humanoid beast dubbed the "Demogorgon" by the show's trio of D&D-loving friends, the creature also enjoys a strange, profound relationship with the telekinetic Eleven (Millie Brown), a bond that has spawned innumerable fan theories since the show's debut.

For Steger, playing the Monster was a highly technical and immersive process; in addition to being encased in a giant suit on eleven-inch stilts, he was tasked with puppeteering various elements of the costume while the rest were controlled remotely by animatronic technicians. And as with every other ghastly character he's portrayed, Steger became strongly attached to the Upside Down-dwelling creature in spite of its horrific appearance and penchant for snatching children (not to mention fiercely loyal, bespectacled best friends) from the human realm.

"I love the Monster," Steger told me via phone late last week. "If it wasn't me he would be a dear family member who was in a lot of trouble. A difficult sibling who has bad habits, but you can't help but love them. They're blood, so what are you going to do?"

That sentiment may sound strange to anyone who recoiled into their living room sofa when the Monster appeared onscreen, but much like any actor, connecting and sympathizing with the character he's playing is an essential part of Steger's process.

"When I'm playing a creature like this as well, I ask myself questions, like, 'What's the gravity like where this character comes from?...What's the nature of its own consciousness?'" he said. "It's obviously not psychologically human, it doesn't have higher brain functions. These are ideas I've been working with for years now, and it's always interesting to me."

Indeed, Steger has long been fascinated by what he terms "evolutionary metamorphosis," and has taken part in various performances that have required him to essentially transform his body for a role. This includes a prolonged stint with the progressive rock band Tool during their Lateralus concert tour, during which he was required to hang upside down 30 feet above the stage (among various other feats) in arenas around the world (he also appeared in the music video for the group's 2001 single "Schism," embedded below).

"Once you become accustomed to whether it's the suit or heavy prosthetic make up, whatever it is you're in, you become it," said Steger of his methods. "It's your second skin. You really feel, at least for me, I feel like I am this creature now. I use how it's changing me psychologically."

So what is the Monster, exactly? For his part, Steger described the fearsome creature as both a "predator from nature" and an "octopus," while also nodding to the fictional monsters that inspired its design as well as his performance: "My personal influences as far as the cinematic influences, I have John Carpenter, I have the Alien films," he told me. "Hammer horror films were a big influence on me. The early great classic universal horror films from the thirties and forties with Karloff, Lugosi, and Lon Chaney, Jr. Those were all inspirations for me as well."

As for the Monster's mysterious but obviously significant relationship with Eleven, Steger is as much in the dark as the rest of us when it comes to interpreting the Duffers' intentions. That said, he admitted it had "crossed [his] mind" that the creature manifested directly from Eleven's nightmares -- a theory that was given some credence via snatches of dialogue but which has by no means been conclusively determined.

"All of these things about Eleven, my relationship, that's all speculation," said Steger. "That's all stuck in the binary brain of the Duffers. ...All I would be able to do is add to all the gossip that's out there about the characters' relationships." Still, he admitted may not be able to stop himself from delving into the numerous fan-driven theories that have sprung up online, which serve as a testament to the series' explosive, and largely unexpected, popularity.

"I'm having trouble keeping up with that to tell you the truth," he said. "I'm going to start exploring it a little bit more. This project, when I got involved with it I knew I was working on something special, something that I would feel good about, but I don't think anybody realized that it was going to be quite the pop cultural phenomenon that it has become, which is pretty interesting. It's interesting to watch how it propagates and sort of expands exponentially."

You can check out more of Steger's performance work hereStranger Things Season 1 is currently streaming on Netflix.

Mark Steger                                                                                         Photo Credit: MarkSteger.net

A former contributor to sites including MTV's The Backlot and Bloody-Disgusting, Chris Eggertsen worked in film development before indulging his love of pop culture writing full time. He specializes in horror, the intersection of social issues and entertainment and Howard Stern. He's on Twitter @HitFixChris.