Done on my DIY modular synthesizer, this patch does its own thing without any sequencing or MIDI input. On oscillator is set to an LFO sort of frequency; there are two state variable filters (one used as low pass, one as band pass), set to maximum resonance, and a whole lot of weird cross-modulation and feedback, as well as some spring reverb.
The synthesizer is just doing its thing for the duration of this recording, no parameters are being tweaked.