Tailed Beast Rasengan

The Tailed Beast Rasengan is an incomplete technique of Naruto Uzumaki. It attempts to use the Rasengan's form to create a substitute for the Tailed Beast Ball.

Background
To get around the fact that he could not originally use either the Tailed Beast Ball or Shadow Clone Technique while in Nine-Tails Chakra Mode, Killer B advised Naruto to use his chakra arms instead to attempt to create a Rasengan.

At the start of his training, Naruto finds some difficulty making the ratio of blue and red chakra 8:2. Despite the fact that Naruto was in his Nine-Tails Chakra Mode, he still sustained injuries on his hand when practising the technique. Naruto asks Killer B to watch and tell him when he has got the ratio right so he can remember the feel of the technique. Naruto has also noted that this new Rasengan is quite heavy, as he can barely hold it up. This is likely because of the Nine-Tails' chakra, which has been described as very dense in previous instances. According to Killer B, he has almost perfected it, and the best way to learn and master it was from real-life experience on the battlefield. Later, during the Fourth Shinobi World War, after gaining Kurama's cooperation, Naruto gained the ability to use the Tailed Beast Ball, and subsequently, developed the Super Mini-Tailed Beast Ball, leaving the completion of this technique unnecessary.

Trivia

 * The positive and negative chakra are coloured differently in the anime, with red for negative and blue for positive.
 * In the anime-exclusive Power arc, Naruto managed to create an incomplete yet effective Tailed Beast Rasengan (before he had absolute control of the Nine-Tails' chakra) which was able to petrify his Nine-Tailed clone.