Songfacts®:

• This is one of the few Soundgarden songs with a lyric written by someone other than lead singer Chris Cornell; it was composed by the band's guitarist Kim Thayil, who also wrote the music for the song. He got the idea for the track during a jam session with Greg Gilmore, who had played drums in the band Mother Love Bone. When Thayil and Gilmore hit on an unusual time signature, they started talking about it and Gilmore identified it as 9/4, which Thayil decided to work with.
• It was the unusual time signature that informed the lyric to this song. Kim Thayil wasn't so much trying to tell as story as to find sounds that would work with the music, which is how you end up with "Mercurial mind the fire, ferrivorous directions and drive."
  
  In our 2014 interview with Thayil, he explained: "I don't just glue lyrics to music. I try to get a feel for the song, what it evokes with me."