The Serpent's Pupil

is episode 113 of the Naruto: Shippūden anime.

Synopsis
Orochimaru's current body is at its limit, and the time to change bodies draws closer. Kabuto tries to ease Orochimaru's pain through medicine, knowing that Orochimaru's body is at its limit and Orochimaru is holding on through sheer will. Orochimaru is excited at the thought of finally acquiring Sasuke's body and Sharingan. He begins thinking of his journey of trying to acquire the Sharingan, from his failed attempt at Itachi, to everything he's done to acquire Sasuke. A lightning based chakra pierces through the door of Orochimaru's room towards Orochimaru. He blocks the technique with his forearms. Sasuke reveals himself and explains to Orochimaru about how pathetic Orochimaru is compared to the Uchiha's. A battle begins where Sasuke looks to have the advantage until Orochimaru switches to his true form, making Sasuke switch to his Cursed Seal Level 2.