Buster

Buster is Andy's pet dachshund in the Toy Story series.

Toy Story
In Toy Story, Andy receives Buster as a puppy for his Christmas present at the film's resolution. Buster isn't seen, but he can be heard barking, and Andy says, "Wow, a puppy!" Both Woody and Buzz exchange worried smiles when they hear Andy say this.

Toy Story 2
In Toy Story 2, Buster makes his first appearance as a brown miniature dachshund. He is able to understand the toys when they talk to him and is shown to be friends with Woody. He is first shown as he bursts into Andy's room to find Woody, and after he takes Woody out of Andy's backpack, he pins Woody to the ground and growls at him, but quickly begins to lick him repeatedly after sensing that Woody is actually alive.

Woody then asks Hamm how Buster did, and it is revealed that Buster set a new record of 13.5 seconds, as shown on Mr. Spell. A little later, when Andy's mother takes Wheezy with a broken squeaker, out to be sold at a yard sale, Woody, thinking quickly, whistles for Buster (though he had to use his other arm due to his good arm having been inadvertently broken by Andy earlier), and he takes him out to the yard sale (though Buster, when told to be "subtle," does it in an exaggerated manner before Woody pointed out he didn't mean that level of subtlety), where Woody climbs into a box to dig out Wheezy and bring him back to Andy's room. Unfortunately for Woody, Buster jumps over a toy while heading back to Andy's room, causing Woody to fall -- which leads to the events of the movie.

At the end of the film, Buster is shown alongside Slinky, who understands that Buster wants to get out of the room, and Jessie performs a stunt with a Hot Wheels car and track to reach the doorknob to let Buster out. He is last seen when Woody sees Andy, Molly and their mother go out for another family outing.

Toy Story 3
In Toy Story 3, Buster, now 10 years older, makes his final appearance. He is now very old, mixed brown and a little gray, has a gray-white snout, is fat, and doesn't seem interested in helping Woody and his friends, even though he continues to remain friends with them.

After seeing his friends getting thrown away by Andy's slightly aged mom, Woody, thinking quickly, whistles for Buster for help getting downstairs to rescue his friends from getting thrown away. However, after Woody hops onto Buster's back so he can run outside to save his friends, the elderly dachshund instead yawns and falls fast asleep on Woody. Then, Woody turns Buster around for air.

Buster is last seen being with a 17-year-old Andy when he departs for college, telling his pet dog to keep Molly away from his stuff.

Early Life
Because he was still somewhat young in Toy Story 2, Buster was energetic, smart, and playful around Andy's toys, but whenever Andy was present, Buster acted like a confused dog. Buster is considered to be nice to the toys in Andy's room and is fiercely loyal to Woody.

Current life
In Toy Story 3, Buster is now an elderly, obese wiener dog who is a teensy bit weak to help Woody and his friends out, even though he remains nice and friendly to them.

Trivia

 * An early version of Buster, named "Speck" by the toys, appeared in the Toy Story comic story "Pup and Circumstance," printed in the November 1996 issue of Disney Adventures. The character's name in the story was oddly not corrected when it was reprinted in the September 2005 issue.
 * In Toy Story 2, Buster's ears are longer than his older self in Toy Story 3. The reason for this was probably to make Buster look more close to an appearance of a real wiener dog and can be considered a goof.
 * Real life dachshunds are believed to have a lifespan of around 12 years, so Buster would be considered quite old, 10 years old by Toy Story 3.
 * Buster is one of the few non-toy Toy Story characters who know toys can come to life.