Orochimaru vs. Jinchūriki

is episode 42 of the Naruto: Shippūden anime.

Synopsis
Naruto, in his four-tailed form, attacks Orochimaru, and devastates the surrounding landscape, also preventing Sai and Yamato's wood clone from approaching him. The majority of Orochimaru's attacks prove to be ineffective against Naruto, but he still manages to keep up with Naruto with his Regeneration Jutsu. Meanwhile, Kabuto advances toward Sakura and Yamato, deducing that Sasori has died. Orochimaru finally manages to strike Naruto with his Sword of Kusanagi, even though he fails to pierce the sword through him. Seeing Naruto in his four-tailed state, Sakura is awestruck and terrified.