Most of the physical art I do these days is on the top of guitar pedals. In this case, I used spray cans to do some colour splatters then drew the tentacle with pain markers before giving everything a couple coats of clear gloss for protection.
The theme was derived from the name of the circuit itself, as it’s based on the Tentacle pedal, by Earthquaker Devices. I picked up the circuit board from PedalPCB.