They accidentally got onto the Billboard charts with this song. It has also been turned into a children's book. There are lots of theories about why it is so brilliant, but so far I think it is awesome because the writers use all the usual tricks to go to a really unusual place. It asks a question that none of us has really asked yet.
What does the fox say? No really, what does he say? How does it communicate?
No matter how ridiculous and irreverent, it busts open the conventions of what all the regular questions songs ask. "Does he love me?"Do I love her?" "What does it all mean?"
Instead, they put all their chops to work. Maybe, just maybe...the fox and the horse communicate by Morse code.
What would happen if we asked and heard all the questions, not just the ones we are expecting.