Kamigakari

Kamigakari (神憑, literally meaning "God Possession") is an ability which allows the user to manifest and materialize their "will" into a black substance or material for different purposes.

Usage
Upon being sealed by her two sons, Kaguya Ōtsutsuki formulated a plan that would result in her eventual resurrection. This led to the creation of the sentient-being Black Zetsu who, as an extension of her will, would enact this plan.

She later demonstrated this ability by taking over living beings.

Madara was able to use a variation of this technique in the form of black rods. He was not only able to remotely manipulate the actions of those embedded with the rods, but also manipulate the rods imbued with his will telekinetically.

Will in in form of black rods also serves as chakra conductors and can be used with Six Paths Technique through Outer Path.

Similar Cases
After her death, Karura's will inhabited her youngest son Gaara's sand, causing it to automatically protect him whenever he is in danger. Gaara's sand morphs to her appearance after this is revealed by his father.

Like its creator, Black Zetsu was also able to subtly influence the thoughts of others, or forcibly make them do his bidding by directly channeling its will through them.

Trivia

 * Kamigakari (神憑) refers to objects capable of attracting spirits and kami, granting them a physical space to occupy.