The Black Transformation…!! (黒き変貌…!!, Kuroki Henbō…!!) is chapter 334 of the Naruto manga.
Kakuzu collapses. Kakashi turns his attention to Hidan and tries to finish him too, but is repelled by Kakuzu. Kakuzu reveals that he has four extra hearts stored within masks on his back, only one of which Kakashi destroyed. Shikamaru is forced to release Hidan, and Hidan wastes no time in engaging Kakashi in close combat. Kakuzu uses his extra masks to attack them from afar with elemental blasts which Hidan, being immortal, survives and Team 10 has difficulty avoiding.