Infinite Tsukuyomi

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

Description
The user creates an empty dimension under their control, which can then be filled with the contents of their desire, using the power of the Shinju to do so. While physically tethered and connected to the Demonic Statue of the Outer Path, Madara was able to cast this genjutsu using only a standard Sharingan. After doing so, Madara could manipulate the otherwise blank and white world to create anything he wanted, no matter how detailed.

To trap every living being in the world within this genjutsu, however, the Shinju's Rinnegan 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.

Upon the technique's activation, the light from the moon's eye illuminates the entire planet, turning it bright as day and making it impossible to escape. All living things are bathed in its penetrating light and immediately placed under the genjutsu. This causes the Rinnegan to be reflected in their eyes as they are rendered immobile, though their cognitive abilities remain unimpaired. The user can then use the God: Nativity of a World of Trees technique to ensnare the targets, assimilating their life force with that of the Shinju. Once this is done, the person is locked in a permanent genjutsu, in which they experience a dream world based on their individual desires, yet will live forever due to the Shinju's power. Those tethered to the Shinju will eventually be drained of everything they once were and reduced to a shell of their former selves, becoming White Zetsu, ideal soldiers for Kaguya.

Countering
Despite presumably being the most powerful genjutsu in existence, the Infinite Tsukuyomi can be countered through specific means:
 * The user's Rinnegan only reflects off of the moon for a limited period of time after the technique has been activated, allowing those who avoid its light to avoid being trapped within the genjutsu. Sasuke Uchiha was able to use his Susanoo to shield himself and his former team.
 * Reincarnated shinobi are not affected by this technique, nor are White Zetsu clones and Black Zetsu.
 * As the genjutsu is cast using the Rinnegan, it can presumably be countered by another Rinnegan.

Known Dreams
After being trapped in this illusion, several characters' dreams were shown:
 * Hinata Hyūga: A couple with Naruto Uzumaki.
 * Kiba Inuzuka: Hokage, declaring a national holiday for dogs.
 * Shino Aburame: Discovering a new insect species.
 * Chōji Akimichi: A girlfriend who loves him for his weight, providing a lot of food.
 * Shikamaru Nara: Seeing both his father and teacher with their significant others, declaring to Temari he won't even bother getting married.
 * Ino Yamanaka: Having both Sasuke and Sai fight over her.
 * Rock Lee: Successfully defeating both Naruto and Neji and gaining the love of Sakura Haruno.
 * Tenten: Having both Rock Lee and Might Guy acting like adults.
 * Mei Terumī: Getting married, with the other four Kage in attendance.
 * Tsunade: Dan Katō as Hokage, reunited with the other Sannin and Nawaki.
 * Gaara: His entire family together and happy, himself friends with Naruto at a young age.

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 that Akatsuki had captured at that time.