Infinite Tsukuyomi

The is a technique which is the key to Madara's Eye of the Moon Plan.

Description
By establishing eye contact with only a standard Sharingan, the user can create an empty dimension under their control, which can be then filled with contents of his or her desire, using the power of the Shinju to do so. While physically tethered and connected to the Demonic Statue of the Outer Path, Madara can manipulate the otherwise blank and white world to create anything he wants, no matter how detailed. By doing this he can create a world exactly as he wants.

To utilise this genjutsu onto every living being in the entire world, however, the Shinju's eye must be reflected off of the moon's surface. In order to do this, with the exception of Kaguya who ate the Shinju's Chakra Fruit, one must first become its jinchūriki. The genjutsu can be cast using the eye that blooms at the top of the Shinju's original form or the third eye which opens on the jinchūriki's forehead when they approach the moon while having the power of the Rinnegan.

Upon casting, the light from the moon's eye illuminates the entire planet, turning it bright as day and making it impossible to escape. Every single person and animal bathed in its light is immediately placed under the genjutsu, with a Rinnegan pattern appearing in their eyes, though they temporarily retain the ability to think normally. Upon capturing the victims, the user can then use God: Nativity of a World of Trees to capture the bodies of living beings throughout the world and assimilate said persons into the Shinju. Once this is done, the person is locked in a permanent genjutsu yet will live endlessly due to the the Shinju's power.

Defences

 * Sasuke Uchiha was able to use his Susanoo and presumably the power of his own Rinnegan to counter the effect on himself and those shielded by him.
 * Reincarnated shinobi are not affected by this technique, nor are Madara's artificially created minions.

Limited Tsukuyomi
In Naruto 6: Road to Ninja, Obito casts a trial version of the Infinite Tsukuyomi, the, on Naruto and Sakura, which provides the alternate reality setting of the movie. Instead of casting it off of the moon, he instead used a crystal ball to serve as a medium to cast and host the alternate world.

Trivia

 * In Naruto 6: Road to Ninja, when Obito uses the Limited Tsukuyomi and the reflected eye of the Ten-Tails appears, it has seven tomoe, representing the number of tailed beasts Akatsuki had captured at that time.