Right to me that sounds like a square wave (possibly wiv 2 occilators one a whole octave higher than the other) wiv a filter envelope (low pass) no attack a little decay no sustain an a little release. To get the wobble effect it sounds like its just been resampled an put in a loop to make it reverse when u hold a note?
If u need a better explination tell me wat software you are using an i may be able to do a step by step
sounds very easy to make i would if i had fruity out here but unfortunatly im over a 1000miles away from where i reside.
kl ok get the malstrom up an when u resample stick it in nnxt and loop bw an fws should give the wobble affect as long as u leave some release if the release aint doin it play wiv the sustain. safe happy bass making!