From Zappa Wiki Jawaka
Guitar Player (1993) Interview:
[FZ:] I was in the studio mixing some other tapes, and the band that's playing on The Blimp is actually the The Mothers. The vocal on The Blimp was recorded by telephone. He had just written these lyrics, and he had one of the guys in the band recite it to me over the phone. I taped it in the studio, and recorded it onto the piece of tape that I had up at the time, which was my track. So, that's how that came about.
[GP:] And now your version of The Blimp is out on the re-release version of Weasels Ripped My Flesh too.
The guy reciting the words was Jeff Cotton (Antennae Jimmy Semens).