It's just exploding with creativity and craftsmanship throughout the album. The opening tune (21st Century Schizoid Man) was unlike anything anyone had ever heard at the time it was released, and there's honestly still not much like it out there. And the transition to Moonchild after it is equally mind-blowing just for the contrast alone. The title track remains one of the most incredible things I've heard.
Zappa also has a lot of good candidates for this list. I'm soft for Freak Out, where the madness started, but some might argue something like Joe's Garage is a better example.