With his series of music videos completed, Chris produced two great commercials. Then the opportunity arose for him to work with Aphex Twin's music to produce a short abstract film like the one he attempted with Second Bad Vilbel. That became flex, which was commissioned by the Anthony d'Offay Gallery for a month-long exhibition with sculptor Ron Mueck. Since I haven't seen most of this short film, I'll insert a description written by Lorraine Whelan in her very informative article for CIRCA Art Magazine #103, Spring 2003.
In a nutshell: from darkness a beam of light illuminates the naked forms of a man and woman who are first seen in the protective spoon embrace; on separating they are both overwhelmed by violence to each other, and the video ends with the woman crawling back to the embrace of the man. The video is filmed in such a way that the human forms are 'other' in that the perspective is distorted and details are too defined. What one hears is a type of hyper-realism (movement, breathing, the meeting of flesh on flesh) and the familiar Hollywood notion of a space vacuum - the impossible sound of the hollow scraping of air... While the video seems to be black and white (as a viewer I found some irony here as I thought of Guinness commercials gone terribly, terribly wrong!), there are subtle hints of colour: the man's ear and the woman's lips are pink. Both the man and woman have very fit, muscular bodies and their interaction is predicated by the white light - at some points they seem to be interrogated, their actions and violence towards each other seem to be caused by this light.
Only flex's intro turned out the way Chris envisioned it, however. The 35mm camera they used proved too bulky. Chris told Director File back in 2000, "It was a slight detour and an experiment to me. It is a short film where i wanted to try and get my interest in anatomy and figurative drawings out of my system. It was intended to be completely abstract but it didn't quite work out that way and although it feels like its trying to say something, it isn't."

The short premiered at the Anthony d'Offay Gallery September 15, 2000. Most notably it was part of a controversial exhibit at the Royal Academy of Arts entitled Apocalypse: Beauty and Horror in Contemporary Art, curated by Norman Rosenthal and Max Wigram, which ran from September 23 to December 15.

You can see the first 3.5 minutes of flex on his Directors Label DVD.

flex even got a 9-minute televised panel discussion on RTÅ 's The View in Nov 2002.

See coverage of Apocalypse at the Guardian:

Loving the Alien - September 27, 2000
Shock art with horror for all to enjoy - September 20, 2000
The end of the world as we know it - September 21, 2000
It's just hell, darling... - September 24, 2000
Charlotte Raven - September 26, 2000

The Times of London documented the controversy over Apocalypse, but their articles don't have permanent links, and registration is required:

Royal Academy art 'belongs in a horror show' .. August 21, 2000
RA chief suffers for shock tactics .. August 29, 2000
Back to the Affront - (opinion) .. August 21, 2000
RA's art for today: just horror, trash, porn. . . .. September 20, 2000
What's cooking in Hell's kitchen? Kitsch .. (review) .. September 20, 2000

In 2003 music video and commercial director Paul Hunter referenced flex in his video for "Superman" by Eminem. In one scene Eminem, set in a black studio, lies amidst a screen full of almost-naked girls, reminiscent of one scene in flex where the man and woman are multiplied in post to fill up the screen.

Adrian Z. keyed us into this fact: Madonna used portions of flex in her 2004 Reinvention Tour. The images are behind her when she sings Frozen. With much respect to Madonna, this one you gotta see up close.

Many of the award bumpers at the 2005 MTV Video Music Awards used some of Chris' audio stylings from flex. Most notably Best New Artist used that phaser sound of the light-of-God moment.

And in 2007, Sidaction, a French association against AIDS, commissioned director Dimitri Daniloff to film a commercial that is essentially one huge rip-off of flex, albeit for a good cause and with an hourglass.