We'll have to keep an eye out for this bloke. According to his site, he performed a few months ago in Tokyo and Toyama so it looks like he's getting active again.
The worst thing you can say to an artist: It's been done before.
And it has. About 30 years ago, there was a European performance artist who didn't just simulate excreting paint like this lame guy, this artist gave himself paint enemas and then crapped it out onto a canvas. He also used to pump paint up his urethra and then pee it out to make a painting. I have forgotten the guy's name, or I would do a web search and find some pics, so, mercifully, you are spared having to view this original guy in action.