The tune’s main groove starts out innocently enough, propelled by this single-note I-chord 12/8 shuffle riff in E [Ex. 1]. Notice that the pick only strikes the lowest string. The fourth and fifth strings are plucked by the middle finger (m). I play the exact same lick over the IV chord, A7, by simply shifting the same lick up a string [Ex. 2].

The turnaround is where things start to mutate [Ex. 3]. After the B7#9 and A7 strikes on every other eighth-note pulse of the first two bars (this classic rhythmic smack-down sounds great against the 12/8 background groove), we reach bar 3, where I play a squirrelly little sweep lick that’s directly inspired by a George Benson move. The C9-B9 shift in the last bar really screams because in addition to the thick, furry overdrive I have going, each of these two-note grips features an artificial harmonic plucked on the lower string.

The heart of this tune—the place where I really, so to speak, get my gristle on—is with the screaming harmonics overdub I play over the main groove. For the I chord, I strike harmonics on the lowest four strings at the 4th fret, dip them down a whole-step or so using the vibrato bar, and then, as I release the bar, bend the fifth string up a whole-step by pushing on the string behind the nut [Ex. 4]. That extra bend really sounds freakish! I do the same thing for the IV chord, but apply the behind-the-nut bend to the fourth string instead. With a wailing tone, these harmonic chords sound utterly diabolical—like a whistle on a mutated train roaring towards you.