Infinite Tsukuyomi

The Infinite Tsukuyomi is an extremely powerful genjutsu that traps the entire world in an illusion, enslaving the human population in a dream so that their chakra may be drawn upon by the God Tree.

Overview
To cast a genjutsu of this scale, the user's Rinne Sharingan must be reflected off of the moon. The exact method of achieving this varies from user to user: in the anime Kaguya Ōtsutsuki uses Yomotsu Hirasaka to create a portal to a dimension containing a moon; Obito Uchiha produces the Ten-Tails and transforms it into a construct of the God Tree, which has a Rinne Sharingan within the blooming flower at its top; Madara Uchiha, per his Eye of the Moon Plan, flies into the sky and reflects his own Rinne Sharingan off of the moon.

Once cast, the penetrating light of the Infinite Tsukuyomi shines across the world, bright enough to dispel the night for as long as it is active. All those who fall under its gaze are trapped in the genjutsu, with the Rinnegan's design appearing in their eyes to represent its influence. Victims of the Infinite Tsukuyomi are rendered immobile so long as they are under its effects, allowing them to easily be wrapped by the bark of the God Tree's roots using God: Nativity of a World of Trees. Over the course of years, humans connected to the tree in this manner are gradually drained of their life energy, personalities and defining features, reducing them to shells of their former selves and ultimately converting them into White Zetsu while at the same time, producing a new Chakra Fruit in the process. The user can also draw upon the chakra of those bound to the tree, causing it to erupt from the ground and enter their own body. In the anime, the technique seemed to need perfecting as Kaguya discovered in her first usage: most of those trapped in Infinite Tsukuyomi such as Haori died after being trapped in the genjutsu instead of being converted into White Zetsu.

Certain individuals are immune to the Infinite Tsukuyomi. The dead, such as those brought back with the Impure World Reincarnation, are impervious to the Infinite Tsukuyomi. White Zetsu, Black Zetsu, and those whose body Black Zetsu coats are also unaffected. However, a foreign soul that has taken over the body of a White Zetsu is still vulnerable to the genjutsu. A Rinnegan user can block the light of the Infinite Tsukuyomi, saving themselves and those within their range from its control. In fact, Rinnegan users, through the combination with the chakra of the nine tailed beasts, are the only ones capable of ending the Infinite Tsukuyomi and releasing those trapped within its dreams. Should these be possessed by two different people, they must form the rat hand seal together in order to release the technique.

Known Dreams
Those under the influence of the Infinite Tsukuyomi experience dream worlds where their deepest desires are fulfilled. Only a select few of these dreams have been seen:
 * Hinata Hyūga is in a strong and happy relationship with Naruto Uzumaki. Neji Hyūga is also alive and watching her from afar with Hanabi Hyūga.
 * Kiba Inuzuka is a Hokage, a position he uses to declare a national holiday for dogs. Also, in the anime, all citizens of the village are to have a dog as a pet/partner.
 * Shino Aburame discovers and tames a giant new insect species to ride.
 * Chōji Akimichi has a girlfriend who feeds him and loves him for his appetite. Chōza Akimichi is proud of his son.
 * Shikamaru Nara decides to never get married to which Temari agrees. Asuma Sarutobi and Shikaku Nara are also alive and enjoying their respective families.
 * Ino Yamanaka is loved by Sasuke Uchiha and Sai who fight for her affection. Inoichi Yamanaka is alive and proud of his daughter.
 * Rock Lee wins the love of Sakura Haruno by defeating Naruto and Neji in a fight.
 * Tenten is a member of a complete and mature Team Guy. In the anime, everyone she knows have polar-opposite personalities and she is a famed weapons master. Furthermore, as Tenten had made direct contact with the Treasured Tools of the Sage of Six Paths just before being caught, she retained her memories of the war and was fully aware that she was inside a dream world.
 * Mei Terumī gets married, with the other Kage attending the ceremony. In the anime, Chōjūrō and Ao attend her marriage.
 * Tsunade lives in a Konoha where none of her loved ones died and none of her friends turned against the village while Dan became the Hokage. Furthermore, in the anime, Konoha's peace and prosperity prompts Jiraiya to write a book about it.
 * Gaara has a happy childhood with his parents, siblings, and uncle and he gets to play with Naruto whenever he wants.
 * In the anime, Yamato becomes the official leader of Team 7 (which includes Sasuke) and is respected throughout Konoha.
 * In the anime, Killer B goes on an adventure with his fellow jinchūriki and their tailed beasts, saving a princess from Akatsuki.
 * In the anime, Karin gets revenge on Zōsui and has Sasuke, who is the Hokage, smile kindly at her again.
 * In the anime, Sai learns to properly express himself again and the entire village comes to admire his smile.
 * In the anime, Kankurō creates the ultimate puppet, which is a giant transforming robot.
 * In the anime, Temari is respected by her siblings so much, they constantly ask for her advice.

Trivia

 * can also be translated as "dreams", "fantasy", or "visions", which fits the nature of this technique.
 * Black Zetsu revised the Stone Tablet to state that the Infinite Tsukuyomi is the salvation for the Uchiha Clan and the key to world peace, something Madara believed in.
 * Sasuke referred to this technique as a genjutsu cast by the Rinnegan. In the anime, Black Zetsu also connects the technique to the Rinnegan.
 * In Road to Ninja: Naruto the Movie, Obito casts a on Naruto and Sakura, sending them to a Genjutsu World housed within a crystal ball. As Akatsuki only has seven tailed beasts at the time, the Rinne Sharingan used has only seven tomoe.
 * Hagoromo believed that in the past, Kaguya had utilised her Byakugan in some fashion when casting the Infinite Tsukuyomi.
 * In the anime, decades later, Boro would use tales of Infinite Tsukuyomi to persuade many people into joining his cult.