Probably Pauls idea.
They were experiementing with all types of different instruments and sounds during the period and they probably just figured that the sound of Pauls bass through a fuzz box would be neat on the tune.
Theres actually two bass parts to the song.
Thanks, Dude, you made me go back and listen to the song AGAIN :-) I've always loved it, and never did figure out what that fuzz bass thing was.
From what I can hear, the standard bass sound is doubled with the "fuzz" sound most of the time, but SOME of the time there is a standard bass that is not doubled with the fuzz ... in other words, normal bass notes that don't have a doubled "fuzz" sound.
Is what you are saying this:
1) There was one bass line played, and the only output was a fuzz.
2) There was another bass line played, doubling the fuzz most of the time, but doing some of it's own stuff sometimes too.
?
Thanks!