<P> "The Man with Two Brians" is the fifth episode in the seventh season of the American animated television series Family Guy . It premiered on Fox in the United States on November 9, 2008 . The episode centers on anthropomorphic dog Brian after he is injured during a stunt being enacted by his owner, Peter, after he watches Jackass with his friends . The family comes to realize that Brian may be getting too old, so Peter brings home an optimistic new dog . Brian is prompted to leave when his family begins to favor New Brian over him . </P> <P> The episode was written by John Viener and marked the directorial debut of Dominic Bianchi . It received generally favorable reviews from critics for its storyline and various cultural references . According to Nielsen ratings, the episode was viewed by 8.60 million households in its original airdate . Johnny Knoxville, Will Sasso and Camille Guaty provided guest performances in the episode . </P> <P> After watching Jackass, Peter and his friends, Cleveland, Quagmire, and Joe are impressed into filming their own highly dangerous stunts . In one stunt, Peter attempts to jump a lake but instead crashes into a tree, causing him to fall into the lake and become incapacitated . Brian swims out to save him from drowning, but strains his back during the rescue and also ends up stranded in the water along with Peter, before being rescued by Joe . Lois berates Peter for his actions, since Brian is becoming old and has been smoking and drinking . Peter begins to grow upset about Brian's age so he obtains another dog and names him New Brian . His positive attitude and desirable personality make Brian feel like an outcast and Brian becomes sad that he is now unloved, and rejected . For example in one scene, when the Griffins hear New Brian fart, they think it is cute and when Brian does it, they get furious and kick him out . He ultimately decides to leave the residence, while his family begins to miss him . </P> <P> Meanwhile, New Brian's constant cheerfulness begins to aggravate Stewie . Stewie pleads for Brian to return, but he informs him that as long as New Brian is there, he has no place in the Griffin household . Stewie reveals to New Brian that they do not like several of his traits, including how he humps the leg of one of their chairs, but New Brian replies by boasting about how he violated Rupert, Stewie's teddy bear . Stewie then brutally kills and chops up New Brian off - screen, throws his remains in the garbage and forges a suicide note . The Griffins then ultimately accept Brian back, while Stewie, traumatized by what happened to Rupert, frantically washes him in the shower while comforting him . </P>

Who does johnny knoxville play in family guy