Plasma Worm is a free (until September 15th) downloadable arcade action game for Windows, and it is an evolution of the traditional snake-eats-the-pellet games that have existed since time began. The game pays homage to Douglas Adams, and the storyline (such as it is) involves the piloting of a plasma worm through a tank within the Improbability Drive, eating stray probabilities that could gum up the engine.