There is such a huge diffrence between production of a track in a recording sense and playing something on bass. I mean I can work on 15 sec of a bass or drum line for days when doing production.
If you really want to get a true dub step wobbel that sounds any where close to something on a produced track you are talking $600-$1000 worth of gear. I can do a detuned, dual occilator sound with my effects rig that can change speed, but I am like $1500 dollars in and still not done. You are never gonna get it perfect in one pedal.
Like FTP said if you really want to do it right you have to have a pedal to produce: octave, square wave, saw wave, detuneing, blending, filtering, LFO to control the signal that can beat sync and sub divided the tempo. And then you have to play and manipulate the LFO tempo to your liking.....Not easy or under $200
If you want something that will get you in the ballpark for under $200 I agree with RCCollins, Tremolo! Seymore Duncan makes one called the shape shifter. It does tap tempo and 4 sub divisions. It has diffrent waveforms and can lag or lead. Get a third hand to attach to the tempo/division ratio and you in the ball park.