The Mice are the secondary antagonists of the Hitchhiker's Guide to the Galaxy.
They are the guises of a pair of scientists who long to consult with Deep Thought and ask about "Life the Universe and Everything."
Role in the film
The computer then volunteered to answer a mysterious ultimate question and create the knowledgable machine we call Earth. Later, the pair take their mouse form and sabotage the Heart of Gold, and later kidnap Trillian, Ford and Zaphod, so they'd use Arthur's brain for experimenting. After a struggle, Arthur kills the mice.
They are the movie version of Frankie & Benjy.