Screaming Skull

The Screaming Skull is a self-oscillating fuzz/overdrive. Used by many seminal bands and users like, Godspeed You! Black Emperor, Mogwai, Black Angels, 2 by Bukowski, Brian Jonestown Massacre, Lee Ranaldo (Sonic Youth), Jakob Ilja (Element Of Crime) and many others.
The Screaming Skull is an overdrive pedal but when oscillator is engaged, turns from fuzzy velcro kind of sounds to aggressive distortion, producing low or high feedback oscillations so the user can produce  variety of tones. Even electro / techno producers use it on live acts… you feel it in your bones.