[1] The "fuzz" concept was accidentally created in Nashville in 1961 by a malfunction in bassist Grady Martin's amplifier during a solo on a track.
[2] The Wah-wah pedal started out as a knob that was created by a British engineer and guitarist Dick Denney in hopes that the guitar would be able to imitate certain aspects of the human voice.
The Fuzz-wah was meant to combine the two unique sounds of "fuzz" and "Wah" distortion, and make them both accessible while a guitarist was playing.
Jerry Garcia, guitarist of the Grateful Dead, used a Morley Fuzz Wah during that band's 1973-74 tours.
Metallica's Cliff Burton used a chrome Tel-Ray Morley Power Wah Fuzz pedal for his solo sound in early days of Metallica (later switched over to Power Wah Boost in order to overdrive front end of the Mesa tube amps better for more or less identical effect).