The Grand Experiment was conceived by the Sith Lord Darth Plagueis's desire to create a life form by gaining control of the midi-chlorians, the sentient microscopic organisms that enabled certain beings to wield the power of the Force. Not only did the Dark Lord deem the project a failure, his efforts ultimately backfired and caused the midi-chlorians to create Anakin Skywalker, the prophesied Chosen One of Jedi legend who was destined to restore balance to the Force by destroying the Sith.
During the late period of the Galactic Republic, the Sith Lords Darth Plagueis and his apprentice, Darth Sidious, conducted the Grand Experiment on the planet Sojourn in 42 BBY. Utilizing Sith alchemy and the dark side of the Force, Plagueis intended to create the living embodiment of the Force. In order to do so, he tried to influence the midi-chlorians in his attempt to create life. But when his efforts bore no success, Plagueis deemed the project a failure. Years later, during the Crisis on Naboo in 32 BBY, Plagueis was surprised to discover the existence of Anakin Skywalker, a young Human boy born without a father. Plagueis concluded that not only had the midi-chlorians resisted his will, but they had also retaliated by engineering the conception of the Jedi Order's long-awaited Chosen One, a Jedi destined to restore balance to the Force by destroying the Sith.
Unlike his master, however, Darth Sidious saw the discovery of Skywalker as an opportunity; the chance to use the Jedi's own legend to the Sith's advantage. After assassinating Plagueis, Sidious—under the guise of his public persona as Supreme Chancellor Palpatine—befriended the young padawan, intending to slowly corrupt him over the years until Skywalker submitted to the dark side - a goal in which he ultimately succeeded. However, Anakin was eventually redeemed and, turning his back on his Master and the Dark Side, slew the Emperor before finally dying himself.
- Star Wars: Darth Plagueis (First appearance)