Short man that looks like my little brother except my little brother is 2 foot taller than him

The twitchy actions of a nervous person.
Or perhaps the only impersonation that can be made while falling a great distance.

To do a Michael J Fox is to have so much so soon, then lose it all for no real reason. A perfect example of this is England Soccer player Michael Owen who was touted to be the worker next best striker, now he seems to be unable to score at only 29. Jody Morris and Michael Ricketts are two other famous soccer players that are said to have done a Michael J Fox. The term originates from the brilliant actor Michael J Fox who lost it all in his prime when he got Parkinsons disease.