The Eight-Tails vs. Sasuke

is episode 143 of the Naruto: Shippūden anime.

Synopsis
Sasuke takes Suigetsu's blade back and begins fighting Killer B, who shows his skill as a swordsman with his Seven Swords Dance. When Sasuke is injured by the swords, Karin heals him by letting him bite her. Sasuke, Suigetsu, and Jūgo then begin a combined assault on B until he decides to use the Eight-Tails' power. Sasuke attempts to put him under a genjutsu. Killer B then attacks Sasuke with his Lariat, and reveals that he cannot be put under genjutsu. After having his neck blown off, Karin tries to heal him but Jugo stops her, Sasuke is revived again by Jūgo by fusing part of himself into Sasuke, which causes him to regress in age. When Suigetsu fights B, Sasuke unleashes Amaterasu on B, and accidentally gets Karin as well. He later extinguishes the flames on her with his right eye. Sasuke is finally able to subdue him and Suigetsu is left in a jelly-like state due to losing consciousness from B's Tailed Beast Ball. Meanwhile, two Kumogakure ninja watch the fight from a cliff and they notice the Uchiha crest on Sasuke, deciding to rush the news to B's older brother, the Fourth Raikage.