When Donald Trump revoked Obama-era guidelines allowing transgender students to use the gendered bathroom of their choice, Cassils started stockpiling their urine.
For 200 days, the Canadian-born, US-based sculptor and performance artist (who uses gender neutral pronouns) collected their own and others' urine — with the initial plan of sending it to the White House (their lawyer advised against it), but ultimately with the aim of turning it into a piece of protest art.
The result is a minimalist cubic sculpture holding 200 gallons of yellow-brown urine, which, when exhibited, is paired with audio from the Supreme Court case brought by the American Civil Liberties Union on behalf of Virginian transgender boy Gavin Grimm, against his county school board.
Cassils says PISSED is taking attention away from "the salacious genitals of a trans person and making it be about an aspect of humanity".
"It seems like a small thing [denying transgender people access to their bathroom of choice], but it's metaphoric and it's indicative of a larger level of control," they explain.
"No government should be controlling the body of an individual in this way."
With Mr Trump's administration threatening transgender people's right to work in the military and questioning the very definition of gender, Cassils said it was both an important and daunting time to be a transgender artist.
In Australia recently for the launch of their first solo exhibition in this country, they told ABC RN's The Art Show: "We have our work cut out for us right now. It's a very disconcerting time but … it does also make you feel like you like you have a purpose on the planet at this moment."
Performance as protest
Much of Cassils's work — which is currently exhibiting at the Perth Institute of Contemporary Arts — is intensely physical, and sits alongside the endurance work of performance artists such as Marina Abramovic and Mike Parr.
In perhaps the most extreme example, Cassils was coated in freezing gel before being set alight in front of a live audience. Their face, engulfed by flames, was filmed for the 2015 slow-motion video work Inextinguishable Fire, which examines the portrayal of violence in the media.
Cassils has worked as a personal trainer for more than 20 years, and this is often apparent in their work — from presenting their muscled torso painted in gold, to furiously attacking a piece of clay.
The latter work, Becoming An Image, requires Cassils to train for up to eight weeks in preparation.
Performing at the opening of their Perth show in February, the artist furiously attacked a clay monolith while surrounded by an audience in a gallery lit only by the sporadic, blinding flash of a camera.
The experience is disorienting for an audience member, seeing only glimpses of the action.
For Cassils, it's exhausting: after about 25 minutes, when their heart rate is skyrocketing and they feel like they "may fail at the task at hand", they quit the performance — leaving the clay, indented with their blows, to be viewed for the duration of the exhibition.
Cassils says the work references the subjective truths and the violence that escapes the notice of history, and deals with the idea that transgender identities are fluid and "about a continual process of becoming".
Becoming an Image pre-dates the Trump presidency (it premiered in 2012) but has taken on a new lease of life since November, 2016 — in more than one way.
For their 2017 performance work Monument Push, performed in Omaha, Nebraska (a state in which, Cassils points out, there is no law protecting LGBTQ+ workers from discrimination), Cassils used the clay cast from Becoming An Image to create a bronze statue on wheels that weighs almost a tonne.
Cassils then recruited diverse members of the local LGBTQ+ community to push the monument to locations the group had identified as sites of oppression.
Cassils says one man in the audience was a founder of Omaha's first gay pride parade, in the 1980s (an era when "people were so afraid to be 'out' there were people with shopping bags on their heads," says the artist).
Cassils invited this man to the performance after he had told them at a university talk that he was a gay activist but didn't understand "this trans stuff … happening so quickly".
"I asked him to commence the push — which of course he couldn't because it's, you know, 2,000 pounds," Cassils recalls.
"Then these three young gender-nonconforming people came up to help him move the monument.
"And I could see this click in his eyes, when he realised that their legacy and their struggle was linked to his, and because he had literally paved this road for them, they could move this burden — this intergenerational burden of trauma — together."
Cassils says they don't just want to link the LGBTQ+ community together — they also want to speak to the cisgender community and encourage them to engage with transgender rights.
"I think that for me, making work around these issues right now is about trying to create forms of empathy, and … hopefully open their minds a little bit," they say.
"It's not necessarily about educating them per se, but if anything it's about trying to create some moments where people can feel their common humanity."
Cassils' exhibition Alchemic is at the Perth Institute of Contemporary Arts until April 14.