Does anyone know what the "destroy" switch does on the Red River Hexafoil? It sounds like magic in the YouTube demo.
The sound comes in at 15:00 or so in this video
https://youtu.be/NURWUnRKvxE

Some sort of positive feedback?
This is the most info I could muster:

If you're really curious you could probably trace it off that.

Fast response! That's a good clue. I may try that. Thanks.

I guess I could just buy one, too.

It could be taking the Percolator's eletrolytic cap to output instead of ground, or just lifting it from ground. You get some wild sounds doing that.

Excellent! More cool ideas. Thanks!
(Edited to add)
This is looking like a good opportunity for some Reed Ghazala style circuit bending.