Control a Timeline with Mouse Position
Create the MovieClip
Insert a New Symbol and create an animation that is appropriate for a project like this. Quick tip: I did my drawing by importing a bitmap into Flash and tracing it.
Do NOT place the symbol on the stage, let it stay in the Library. Also, make the animation 100 frames long for now:
Don't worry about a stop(); action or a "clean" loop. Let it snap real ugly, like this: