Warning: This article contains spoilers from Sunday's episode of Family Guy, "Life of Brian."

On Sunday, Family Guy viewers were forced to say good-bye to Brian, the family dog that has been a major character in Fox's animated series since it premiered in 1999. For 12 seasons, Family Guy creator Seth MacFarlane voiced the wise, smart-cracking dog, but the producers still thought it a good idea to kill Brian.

Fans disagree.

A petition has formed on Change.org demanding that Brian be re-instated as the Griffin family dog. The petition is direct, titled "Seth MacFarlane, and Fox Broadcasting Company: Bring Brian Griffin back to Family Guy."

"Brian Griffin was an important part of our viewing experience," Aaron Thompson, the petition creator wrote. "He added a witty and sophisticated element to the show. Family Guy and Fox Broadcasting will lose viewers if Brian Griffin is not brought back to the show."

The petition also includes a link to a Facebook page titled "R.I.P Brian Griffin from Family Guy," which promotes the petition and currently has over 386,000 "Likes."

"The writers of family guy didn't just kill off one of their creations, they killed off the dog who has lived in our homes for the last 15 years," Thompson's petition continues. "They killed the dog we all have come to love. They killed America's dog!"

Steve Callaghan, Family Guy producer, thought Brian's death would be "fun."

"...this was an idea that got pitched in the writers room, and it sort of caught fire and we thought it could be a fun way to shake things up," Callaghan told E! Online. "As soon as this idea came up, we started talking about what the next couple episodes could be, and we got very excited about the way this change will affect the family dynamics and the characters."

Callaghan also said that he is not afraid of fan backlash.

"I'm not [scared], only because our fans are smart enough and have been loyal to our show for long enough to know that they can trust us. We always make choices that always work to the greatest benefit of the series," Callghan said.

Over 39,000 signatures on the Change.org petition say that Callaghan may have been wrong.