Warning: This piece contains nudity and may not be appropriate for work.

Cassils, Powers That Be, performance still; The Tip of Her Tongue series, The Broad, Los Angeles, 2016 Photo credit: Cassils with Leon Mostovoy, 2016 Photo courtesy of Cassils and Ronald Feldman Fine Arts

On Saturday evening, gallery guides at Los Angeles museum The Broad ushered visitors, in groups of 15, down a set of stairs to the empty museum parking lot, where they were met with piercing darkness. The crowd sat in a quickly evolving circle surrounding a black mat, its corners marked by four large cars, headlights on, doors open. "It looks like we're about to see a rumble," my friend whispered.

The crowd was settled, with most people hunched on the floor, save for a few sitting inside the parked cars, radios on, each booming a mixture of music, static, talk radio and advertisements. The various snippets all enmeshed and fought to overpower each other, creating a jarring blanket of noise above the seated audience. A Beatles song, the words "black lives matter," Yo Gotti's "Down in the DM," an advertisement for teeth whitener -- chopped and mixed and layered on top of each other, yielding the cacophonous tune of being caught in traffic with your windows down.

Then Cassils emerged. The performance artist was fully naked, and though no one else was visible, their body was quivering, their eyes were panicked. Their hands were tightly crossed in an "X" shape over their chest, painfully still as if being held there against their will or warding off an impending assailant. In a flash, Cassils' body was flung downward by an unseen entity, their flesh crashing to the mat below with the cruel force of someone not treated with human decency. They breathed heavily, heaving, shaking, with twitching muscles and bulging veins creating abstract patterns on the skin that soon faded away to be replaced with new ones. Soon after, another hit. And then another.

Cassils, Powers That Be, performance still; The Tip of Her Tongue series, The Broad, Los Angeles, 2016 Photo credit: Cassils with Leon Mostovoy, 2016 Photo courtesy of Cassils and Ronald Feldman Fine Arts

Cassils is a Los Angeles-based, transmasculine artist, known for using their physical body as a living, breathing, sweating, trembling sculpture. Their piece, "Powers That Be," is a fight between a human being and an invisible other, the identity of which is left up to the viewer's interpretation. Throughout the duration of the piece, Cassils is choked and pinned down, thrashed and dragged, but they also throw wild punches themselves.

"I'm interested in the absence of body, and what my body looks like in relation to that body," Cassils explained in an interview with The Huffington Post.

The radio waves that ebb and flow in and out of recognition not-so-subtly illuminate some of the oppressive and oppressed forces rampant in contemporary society. Mediated through the car radios, the sound samples create a truly Los Angeles experience, the aural equivalent of surfing the internet and being bombarded with images of Syrian refugees and discounted gym memberships in the very same glance.

I want it to be bigger than my own subjectivity, to include other things beyond ... I'm trying to make space so that, you, as the viewer can complete the piece.

"The radio in LA is such a good way of picking up the pulse," Cassils said. "At any given moment you can hear about a woman’s right to choose, a tanning product, a really bad R&B song." Cassils listened to various radio stations that air around 10 p.m., the time of the performance, and compiled a curated simulacrum of the experience at its most grating.

The sounds traveling through the air conjure images of possible entities engaged in battle with Cassils, though each is transient and uncertain. News snippets intermittently describe police brutality and LGBTQ violence, along with more superficial and entertaining sound bites. "With this piece, I want to talk about more than just my body," the artist said. "I want it to be bigger than my own subjectivity, to include other things beyond. Using the airwaves and the absent figure, you can project on that absence all these larger issues that aren’t being spoken about -- issues around race, class, gender, religion. I'm trying to make space so that, you, as the viewer can complete the piece."

Cassils, Powers That Be, performance still; The Tip of Her Tongue series, The Broad, Los Angeles, 2016 Photo credit: Cassils with Leon Mostovoy, 2016 Photo courtesy of Cassils and Ronald Feldman Fine Arts

To train for the piece, Cassils, a former body builder and personal trainer, worked with fight choreographer Mark Steger to master the extremely difficult task of fighting without an opponent. "If you’re punching a punching bag, there is something that will absorb the hit," Cassils said, "and that actually completes the motion. When you’re trying to hit something that’s not there, you have to put force outwards and draw force inwards at the same time. It’s very easy to hurt yourself."

To achieve the illusion of virtually fighting with a ghost, Cassils trained vigorously. "This piece guarantees injuries, basically," the artist explained. In an early rehearsal, they gave themselves a concussion from speeding up and slowing down too quickly. "Rushing forward and stopping so much like that, you bruise your brain against the inside of your skull."

I see risky as hunching over a computer and eating Cheetos. That’s a death wish.

Steger often choreographs fights for Hollywood movies and TV, including "American Horror Story," and Cassils' work often alludes to the strange conflation of appearance and reality that is particularly pervasive in Los Angeles. During their time as a trainer, Cassils often worked with actors who needed to resemble soldiers. "After the Iraq war broke out, I had all these blonde actresses coming up to me, saying, 'I have to look like a soldier.'" In the strange space of LA, not only current events but the simulation of current events cycle in and out of view.

Although most would describe Cassils' physical performances as intense, if not outright masochistic, the artist emphasizes that they have no interest in inducing agony or risking safety. "I’m not a masochist," the artist said. "It’s not risky because it’s completely controlled. I see risky as hunching over a computer and eating Cheetos. That’s a death wish." That being said, the training process for this particular piece was so taxing, Cassils said they would not tour the work.

Cassils, Powers That Be, performance still; The Tip of Her Tongue series, The Broad, Los Angeles, 2016 Photo credit: Cassils with Leon Mostovoy, 2016 Photo courtesy of Cassils and Ronald Feldman Fine Arts

Watching Cassils be thrashed around by an invisible attacker, and fight back in return, viewers were spotlighted both by the car headlights and an army of iPhones, snapping photos, recording video, uploading and messaging tiny, naked, virtual iterations of Cassils into the ether. However, far from being a distraction to the main event, this became another aspect of the performance.

"I’m interested in the way a document can become its own piece. I want people to use their mobile devices to film," the artist said, hoping to eventually use the uploaded footage as another aspect of the piece. "It speaks to the ways people feel empowered or disempowered to record events in their lives, whether it's an act of police brutality or something funny or a great concert. We're in a time when more people at a concert are looking at their phones than the act, more excited to photograph their food than to savor it. I'm interested in the ways we experience violence when we record; it’s like witnessing something instead of watching a safe spectacle."

We're in a time when more people at a concert are looking at their phones than the act, more excited to photograph their food than to savor it. I'm interested in the ways we experience violence when we record; it’s like witnessing something instead of watching a safe spectacle.

From every angle, with every motion, the potential meaning of Cassils' severe, almost sickening, performance changes shape. For a moment, the staged scene resembles Edward Kienholz’s 1969 "Five Car Stud," about a group of white American men, in front of their pickup trucks, brutally attacking a black man for drinking with a white woman. Is the piece about race? From another angle, we see Cassils in full spotlight, their form rupturing norms of bodily binaries and boundaries, serving as a living manifestation of a life indisputably lived in the in-between. Is this a piece about gender or identity? Commercials blast from the radio waves. Capitalism? The audience films. Passivity?

Just as the viewers begin to conjure in their imagination a potential outline of Cassils' attacker, the artist takes control, pummeling the invisible being with all their might. In the artist's words: "Who could the body be when I am an oppressor?"

Cassils, Powers That Be, performance still; The Tip of Her Tongue series, The Broad, Los Angeles, 2016 Photo credit: Cassils with Leon Mostovoy, 2016 Photo courtesy of Cassils and Ronald Feldman Fine Arts

"Powers That Be" took place on April 2, 2016, at The Broad as part of "The Tip of Her Tongue," an evening of feminist performance art curated by Jennifer Doyle.