"Unfulfilled Scream" (届かぬ絶叫, Todokanu Zekkyō) is episode 79 of the Naruto: Shippūden anime.
Hidan's immortality enables him to stay alive even with his head cut off, although he cannot move his body. Seeing this, Kakuzu sews Hidan's head back on his body with threads that sprout from his body. Izumo and Kotetsu try to attack Kakuzu, but he manages to grab them both by using his body threads, restraining them and suffocating them as well. Hidan, now able to move again, returns to the circle and stabs himself with the blades of his scythe, and he finishes the ritual by stabbing himself in the chest with another spike, fatally wounding Asuma.
When Hidan's decapitated body was shown during a panoramic shot of the battlefield, he had his right side of his cloak, even though it was destroyed during a previous episode by Asuma's Fire Release technique.
Also, when Kakuzu strangled Kotetsu and Izumo, his ring wasn't present on his left middle finger.