Also see Fuuton Rasenshuriken
Naruto's most powerful modification of the Rasengan
so far. It requires 4 shadow clones to create, and resembles a large shuriken made of rotating air.
The Rasenshuriken can be thrown medium-range distances, but it is easy to dodge. If it hits however, it causes massive cellcular damage as tiny blades of wind literally cut each individual cell. An almost certain kill if it is a direct hit.
is so powerful that it damages Narutos hand when he holds it, and Tsunade
warns Naruto that if he uses it too much it could seriously damage his hand.
Naruto has said that this modification is still not the final form of the Rasengan, and that it is still only at 50% strength.