Where do I start?
Ok... I'm gonna assume it's a saw wave or something very similar. Seems too aggressive for a square or triangle and it's definitely not a sine... probably a multi oscillator... maybe 3 saw waves. Spread them apart by detuning them. Sounds like the detuning has a long envelope on it too so it may only move from 2 - 3 semitones difference over time but I think that's what's giving it that width and development. Distortion. Definitely some sort of saturation goin on there. Probably been EQed a tad. Some sort of filter has been given the same envelope timing as the detuning with a little wobble half way.
The pitch has also got and envelope or automation on it to make it drop in pitch.
Cut the bottom out from about 250hz and below, whack a single saw underneath it all with the same pitch automation/envelope.
Repeat with a sub(Sine wave, pitch env/auto)