Personally
I thought it was a little on the short side. The joke is used often and most recently was on family guy, but it's an idea not a stolen animation. All in all the animation was pretty smooth and really the only thing that you could do to make this a lot better is build on the idea and make something a bit longer. Granted, that takes a lot more time with all the script writing, but usually ends up making things more enjoyable, depending on which way you take things and the audience you are aiming for. Good work.