Decent
You had a nice punchline, and a good plot. You could have put tons more effort into the animation though, since it's so short. Was it supposed to repeat at the end though? Or was he approaching another skinny guy? If it wasn't supposed to repeat, I reckon you adjust the actionscript coding so it won't do that anymore. And if he was approaching another skinny guy, then at least make his pants a different colour or give him a moustache, to make him look like a DIFFERENT skinny guy. Not too bad though.