Uncle Bill, with his oh so uncanny knack of squeezing in the unexpected note when no one is watching or expecting, plays a major-keyish bass line to a minor key riff with an EB-3. While the guitars play the A minor pentatonic riff with a minorish C on a revolving basis, Herr Wyman hits a majorish C# whenever the band plays an A (though never when the riff starts) in its riff cycle A, C, D, E,
A, G + A, C, D, E,
A. And it works, adding to the Cajun feel.
https://www.youtube.com/watch?v=9hw1SKn5eFM&list=RD9hw1SKn5eFM&start_radio=1Around the time of Goats Head Soup, he played an EB-3 quite often (though he reputedly didn't really like it in the end).
Even live as this cocaine-crazed version of Street Fighting Man from 1973 shows.