Truth-Seeking Ball

Truth-Seeking Balls are spheres of black, malleable chakra. Originating from the power of the Sage of Six Paths, they are composed of all five basic nature transformations, in addition to Yin-Yang Release, and Six Paths Sage Chakra. They are capable of negating all forms of ninjutsu.

Usage
The Truth-Seeking Balls can be shaped into a variety of forms, allowing them the flexibility to be used for offensive, defensive, and supplementary purposes. Obito Uchiha shaped the balls by having them pierce through holes that temporarily formed in his hands, whereas other users forego this process and simply mould them. The balls can wrap around the user to act as a defensive shield, or be launched to serve as high-speed projectiles. They are also capable of causing massive explosions by rapidly expanding in size.

According to Hiruzen Sarutobi, this technique uses attacks that turn their target to dust in an instant on a similar basis to Dust Release, but on a greater level in terms of shape transformation. This allows it to constantly be used for either offensive or defensive purposes. Hiruzen also noted that, since the substance is a combination of more than four nature transformations, it is neither a kekkei genkai nor kekkei tōta, but greater than both. Tobirama Senju discovered that this technique can utilise Yin–Yang Release to nullify all ninjutsu the balls touch. As a result, any damage done by this technique to a reincarnated individual who can usually regenerate infinitely, cannot be repaired. However, Obito's Truth-Seeking Balls did not nullify ninjutsu prior to him gaining control over the Ten-Tails' power.

Obito used the black substance as chakra receivers, shooting them in six directions to perform the Six Red Yang Formation. The balls can also be used to create the legendary Sword of Nunoboko. The black substance is highly durable, only taking damage from powerful techniques such as the Evening Elephant and a senjutsu-enhanced Tailed Beast Ball. When Kaguya summoned a huge Truth-Seeking Ball, Black Zetsu noted that it could be used to create a new dimension. 

Shape Variants
The balls can be manipulated into a variety of shapes for various purposes.

Drawbacks
According to Minato Namikaze, the user can only control the chakra within 70 metres of their location. He also noted that the chakra simply exists, and can't be deactivated. Hiruzen noted that there is likely a limit to the amount of time that the balls can take on another form. After seeing the effects of Gamakichi's natural energy-imbued technique on Obito, Naruto and Tobirama discovered that the balls were incapable of negating senjutsu. This was further proven when Naruto managed to land a hit on Obito while in Sage Mode. It was also shown that when the transformed balls come in direct contact with natural energy-based techniques, their form becomes disrupted. Additionally, the rapid expansion of the balls is capable of damaging the user's own body if they are not protected by other balls.

Similar to the chakra receivers, the balls will disintegrate if the user's chakra disappears. Any clones produced by the user will not have their own Truth-Seeking Balls. The clones can, however, have the balls passed on to them.

Trivia

 * When a jinchūriki of the Ten-Tails gains control over the beast, the shakujō variant seems to instinctively form in their hand. Obito and Madara Uchiha each wielded one half of Hagoromo Ōtsutsuki's complete shakujō.
 * In the original publication of chapter 689, Black Zetsu lists Wood as one of the component natures of Kaguya's Truth-Seeking Ball, rather than Water. Masashi Kishimoto confirmed this was an error in Issue #41 of Weekly Shōnen Jump, and stated that it would be corrected in the tankōbon release of the chapter.