Midi-chlorians (also spelled "midi-clorians" or "midichlorians") are a microorganism in the fictional Star Wars galaxy, first mentioned in The Phantom Menace. They are microscopic life-forms that reside within the cells of all living things and communicate with the Force. They are symbionts with all other living things and without them life could not exist. The Jedi have learned how to listen to and coordinate the midi-chlorians. While every living being thus has a connection to the Force, one must have a high enough concentration of midi-chlorians in one's cells in order to be a Jedi or a Sith.