Florid Bass by Autosuggestion
Oscillator 2, pitched at a strange sweet spot around a major second + 2 octaves over Oscillator 1, frequency modulates Oscillator 1. The LFO at minimum speed and Key Sync on is acting as a slow envelope on Osc. 2's pulse width. Also try the pulse width at 50% and/or Sync engaged for a slightly mellower sound. Pushing the pulse width up to 80% and you'll lose the lowest bass octave and will end up with a melodic tom.