"Killer B and Motoi" (キラービーとモトイ, Kirābī to Motoi) is episode 244 of the Naruto: Shippūden anime.
Struggling with the Falls of Truth and his darker side, Naruto requests help from Motoi, asking how Killer B overcame his dark side. Due to the seriousness of the situation and the effect on peace that Naruto gaining control of the Nine-Tails would have, Motoi agrees, telling him and Yamato of B's past. After Motoi's father's death at the hands of the Eight-Tails, who had rampaged after his jinchūriki was unable to control it, B was chosen and subsequently shunned as the new Eight Tails jinchūriki. As he had blamed the tailed beast for his father's murder, his hatred shifted to Killer B himself and twice tried to kill him with a kunai; while B seemed to recognise him the first time, the second time, Motoi witnessed the villagers of Kumo bombarding Killer B with eggs, only for the latter to smile and shrug it off. Naruto leaves for a moment of solace, only for Motoi and Yamato to be attacked by the Giant Squid, with Motoi being captured.
Yamato uses his Wood Release: Smothering Binding Technique to restrain the squid, athough Naruto refrains from attacking, believing the squid to be Killer B in his Eight-Tails form angrily attacking Motoi; however, the real Killer B to arrive and quickly defeat the squid. Motoi asks Killer B why he would save someone who tried to kill him in the past, Killer B responds that he does not remember that incident, and that all he remembers is the good memories he had growing up with Motoi, who he proclaims is his best friend. As he gives Motoi a fist bump, which Motoi reciprocates, Naruto adopts Killer B's verbal tic, while Killer B does the same.