Why Tyson did this?

Thoughts?

http://gfycat.com/AnotherLinedFulmar

as a part of this

http://gfycat.com/HarshSkinnyAvians

Tyson's success depended on him being faster than his opponents. Those cat-like hops, albeit exaggerated in his training, was essentially the same move that he'd use in his fights to get an angle on his opponent. You'll often see him do it when his opponent is shelled up and stationary, similar to what a hopping-Pacquiao would do in that situation. He would also do it after slipping the lead when his opponent is slow to adjust.

Against a skilled opponent with closer physical attributes who could make quick adjustments, this technique would be less effective. Other footwork in which you bring the rear foot up depends on avoiding your opponent's hard lead. This can get your butt out of the line-of-fire quick, and/or can also turn into a strong counter punch (e.g. search for greynotsoold's post on the 'Drop Shift' in the 'Useful Posts' section).

plyometrics, explosive movement, I would not read too much into this.

stability/ disorientation/ recovery/ sequencing?

Tyson could slam dunk a basketball like Michael Jordan.