He was on mushrooms and the magnificence of the double rainbow washed over him like a great wave, he had no choice but to drown in it's awesomeness. I'm actually pretty jealous, I've never tried shrooms but if I did I would like to have an epic experience like this.
Haha! He was interviewed and says he wasnt on anything...bullshit. He HAD to be on something. Seriously, I dont think anyone could be that excited about a double rainbow while sober. Plus he says "What does this mean" in it...he obviously took something that was making him think.