This is somewhere between rotoscoping and animation.  Whatever it is, I did it for the Academy of Natural Sciences in Philadelphia’s butterfly exhibit.

I started with footage of a butterfly flapping its wings.  On a frame where the entire top of the butterfly was visible, I traced it out, shape by shape in Shake using the roto shape tool.  Then I tracked the wings and applied the four-point tracker to the shapes that I had traced. Once that was done, I shook off the footage node and exported the composition with the alpha channel to AfterEffects where I rendered it with motion blur.