From Death By Audio:
MYSTERY FUZZ OCTO GENERATOR
The Soundwave Breakdown takes the idea of a screaming fuzz pedal and turns it inside out, utilizing specially matched transistors turned backwards to get its bombastic sound. The exact positions of the knobs yield completely different sounds, ranging from fuzz, buzz, and grind, to bleeps, synth sounds, etc. A vast universe of gnarliness is yours, with octaves, oscillations, and overtones waiting just behind your next solo. Be forewarned, it's only grizzled psycho fuzz all the time.