It's actually pretty simple. I used to be able to play Tommy the Cat since it is mostly repetitive riffs, My Name is Mud is the same way.

The genius in Les Claypool is that he makes something that is actually simplistic sound so much more complex by using the other members of the band effectivley. Not to say that Les isn't a badass on the bass because that man can play shit I couldn't fathom more than a few others could play.