Cave dweller playing in itself?

[icecycle66]

My cave dweller oscillates and shimmy-shakes on it's own.  It has a constant fuzzy hiss going through it.
Is this just because of the normal lack of buffering on the pedal circuit, or did I do something wrong?
Everything is built by directions.
I made this mod to it: http://www.madbeanpedals.com/forum/index.php?topic=4869.0
Here's a video: