It's easy to fall in the trap of writing the same flavor of riff over and over. I like to avoid that trap by starting in a different key, with a different guitar, a different scale--or in this case, losing the pick altogether.

Without a pick, you have to rely heavily on hammer-ons, pull-offs and tapping. I also use some slapping here as well. I also occasionally try to steer away from using phrygian dominant or natural/harmonic minor scales, which are great starting points but force the way your thinking into a box of what notes work and what don't. In this case, I just look for notes from both that keep the vibe of the song chaotic and dissonant. I use a whole tone scale (which sounds a bit like ski-ball) for the fast runs--I like how mood-agnostic it is, almost robotic.

The main riff also originated from practicing AAL's "Cascade".