Dark Rasengan Technique

Shadow Rasengan (シャドウ螺旋丸, Shadō Rasengan) is a powerful technique invented by Paul Gekko (Future), which he created by observing the Tailed Beast Ball. He spent three years developing the Rasengan; his plan was to take the shape transformation of one's chakra to the "highest possible point" and then combine it with his chakra's nature affinity, creating a technique that did not need the aid of time-consuming hand seals to control. He taught it to Paul Gekko and his Future Children and his Future Wife.

Usage
The Rasengan does not require any hand seals to use, relying only on the chakra control of the user. Once it is complete, it becomes self-sustaining, which does not give the Rasengan a definite limit like the Jet Stream Rainbow Bomb. The compacted nature and moving speed of the chakra allows the Rasengan to grind into whatever it comes in contact with to inflict major damage. This tends to launch the target spiralling backward after being hit or, if the target is lying on the ground or being launched to the ground, the destructive force is enough to form a crater. In the anime, Naruto was able to throw the Rasengan, making it a mid-range projectile technique.

Countering
According to Kuro no Mikoto, someone from the Future blocks it's attack to prevent the person from the Present from being weakened.