Genjutsu: Sharingan

Genjutsu: Sharingan broadly refers to a range of genjutsu performed with the Sharingan. It has also been shown to be performed through the Sharingan's higher evolutions: the Mangekyō Sharingan and the Rinnegan.

Usage
By establishing eye contact with a target, the Sharingan user traps them within a genjutsu which can be exploited for one of various purposes, such as: causing instantaneous — but temporary — loss of consciousness or paralysis in the target, forceful extraction of information,  relaying memories, erasing memories, removing genjutsu placed on the target by others, and controlling a target's actions.

Members of the Uchiha clan are particularly famous for using their Sharingan to control the Nine-Tails, so much so that Konoha quickly came to suspect Uchiha involvement in the Nine-Tailed Demon Fox's Attack. Sasuke Uchiha is noted to be able to use the technique through his Rinnegan, to trap all the tailed beasts in a genjutsu with a mere glance.

The illusions created by Genjutsu: Sharingan do not appear to have any trademark form, appearing vastly different between the same functions and even the same users. For example, Sasuke typically uses it to render targets unconscious, yet on the first occasion the target's body is pierced with large feathers, on another, the target is grasped and overwhelmed by a shadowy figure, and on the third the target experiences Sasuke personally stabbing them.

Trivia

 * Sasuke and Itachi Uchiha have both been shown activating their Mangekyō Sharingan to cast genjutsu despite already having their regular Sharingan activated, implying that this technique is enhanced in some way by the evolved dōjutsu, or that there is a similar technique utilised only by the Mangekyō Sharingan.
 * A shadowy version of Sasuke's humanoid Susanoo first appears in a genjutsu he creates, only making a formal début several chapters later.
 * By making eye contact with a jinchūriki, Obito could use this technique to control the tailed beast sealed inside them, while its host remained unaffected.
 * Despite genjutsu working by altering the chakra flow of a target's cerebral nervous system, this technique affected Mecha-Naruto who doesn't have a brain.
 * Madara is shown having to deactivate his Rinnegan to his Mangekyō Sharingan to perform this technique. However, this wasn't required in Sasuke's usage.