The Two Mangekyō

is episode 415 of the Naruto: Shippūden anime.

Summary
Now that its master is nearby, Black Zetsu declares that nobody can stop it from handing Madara the left Rinnegan and the Nine-Tails' Yin half, detaching itself from Obito's body. As Kakashi and Gaara prepare to attack in order to give Naruto the means to survive the tailed beast's extraction, Black Zetsu finds itself unable to leave Obito's body, due to him not allowing it to. Obito questions Madara about who he himself is to the older Uchiha, with the jinchūriki explaining how Obito – as a follower of Madara's ideals – is Madara, he who wishes to cancel the world created by the Sage of the Six Paths and to create a new one through the Eye of the Moon Plan's completion. Seemingly giving in to Madara's words, Obito starts walking towards his ancestor, with Minato trying to attack Madara as Kakashi and Gaara try to stop Obito, only for Madara to effortlessly stop them. However, Obito doesn't take Madara's hand, but instead pierces him in the gut, claiming that his current self is the same as the one who wanted to become Hokage – recalling Naruto's words in the process. Obito goes on to extract fragments of the One-Tail's and the Eight-Tails' chakra, ordering Kakashi to teleport Naruto and Sakura to the other dimension. After Madara stops Obito from going there himself, Kakashi runs to Obito's side, with his old comrade commenting on how Kakashi always looks down upon him, remembering the old times in Konohagakure.

Trivia

 * As in the manga, the spike going through Obito's left hand is missing throughout the episode, but reappears when he enters Kamui's dimension.