I was wondering what happened to that pedal ?
it seems like it hasn't been stolen in 1999, but it's never been used since Washing Machine... that's such a rare and crazy (and expensive) effect pedal, I'm surprised that SY had this in their arsenal but didn't use it more often...
a demo of this weird thing
https://www.youtube.com/watch?v=SNy5FXATIPc
the picture of it in the Washing Machine booklet
and you can see Thurston using it on that Diamond Sea video :
https://www.youtube.com/watch?v=MEXpKDu0Mf8
such a great effect, too bad it's so rare !