Well Im going to disagree with every one else and say that I did not predict the beginning, at least not all of it. I thought he might lose his finger or something, but watching him get entirely sucked in was pretty funny to me.
I thought the end was more predictable, especially on newgrounds where you can almost guarantee that if it made the front page it has a lot of A. Profanity B. Gore C. Sexual Themes D. A combo of all the above.
I think it would have been funnier if after the kid put in the change the guy crawls out of the machine with a beard and a candy bar, mumbling to himself or something.
But maybe thats just me. Either way, you did a great job with the music, animation, and idea. Something tells me you already knew that.