Here was how I replied to this question:
Id love to hear everyone elses opinions and views.Well, to the angler the plastic worm looks like just a worm but truth of the matter is that to the bass, its not imitating a worm. Its imitating many different bottom dwelling creatures. As one person already said, it could be immitating eels if indeed that body of water has them. It can also be imitating leaches. Another thing it could apear to be to the bass are small fish that stay near the bottom called Darters. It could also be immitating many of the different types of amphibians that exist in many of our lakes and ponds. These are only a handful of creatures that plastic worms can appear to be to the bass.
Good Fishin, Jared