A scientist creates a synthetic robot human in his castle laboratory that is incredibly lifelike. The robot gains sentience and, after killing the scientist, begins to build an army of human-like robots in hopes of overthrowing humanity.
A man kills his business partner (who he runs a paper mill with) by throwing him into a vat of acid. The acid is later mixed into solid pulp that's used to produce hundreds of paper products. The victim, working through these products (by animating paper cups, newspapers etc.) gets revenge on his murderer.