Buster is Michael and Amy's pet Bearded Collie dog who only appeared in the Barney & The Backyard Gang video, Waiting for Santa. He was portrayed by animal actor Grouchie. Grouchie was trained by Diane Arrington during his time on set within the respective video.
On Christmas Eve, Buster was wide awake while lying in his dog bed. Once Michael and Amy came downstairs, Buster got out of bed to see who it might've been within the dark room. He eventually went back to his dog bed after he was encouraged to do so by Michael, letting him know that everything was okay.
He would eventually get back out of bed once Barney was yelling for help when he was stuck within the chimney, prompting Barney to mention that Buster's nose was cold as he felt it while being stuck in the chimney. Buster eventually left Michael and Amy to help Barney out of their chimney. Once Barney came into the living room and the Backyard Gang arrived, it was evident that Buster didn't return back to his bed during that time.
Once Barney, Michael and Amy returned from the North Pole within the Waiting for Santa video, Buster was lying back in his bed. He continued to lay in his bed even when Barney was reading Michael and Amy The Night Before Christmas. While the trio was reading the story, Santa arrived with gifts, including giving Buster a dog bone wrapped in a bow.