"Killer B and Motoi" (キラービーとモトイ, Kirābī to Motoi) is chapter 494 of the original Naruto manga.
The Eight-Tails had long been a problem for Kumogakure; the village constantly tried to gain control of its power, but when its previous jinchūriki would fail to contain it the village would suffer heavy casualties. Loved ones of those who died would come to hate the Eight-Tails and its jinchūriki, just as Motoi came to hate Killer B. Although they were friends, Motoi once tried to kill B, but ultimately could not. He nevertheless felt ashamed, something that became more pronounced as the years went by and B became a village hero. Motoi has long feared that B knew of his attempts on his life and hates him for it. Soon after telling this story to Naruto, Motoi's life is saved by B, who in fact did not know and doesn't actually care. Naruto is happy to see them reform their friendship.