Dug

Dug is the secondary tritagonist in Up. He also appears in Dug's Special Mission as the main protagonist and in George & A.J. as a minor character.

Up
Dug is a husky Golden Retriever who belongs to Charles Muntz.

He is a fun loving, dog who speaks English by way of a special collar that translates his thoughts to speech, invented by his former master, Muntz. Early in the film, Dug, one of Muntz's canine minions, is searching for a large bird that Muntz has been trying to capture for decades. He runs into Carl Fredricksen, Russell, and Kevin (the bird he is searching for). However, immediately after meeting Carl, he begins to idolize him and sees him as his master. He winds up switching sides, assisting Carl, Russell, and Kevin.

He is every ounce a puppy, and quickly becomes attached to Carl, who is at first hesitant to accept Dug. When he does, Dug expresses his joy in a manner that leaves no doubt that he prefers his new master.

During the end credits of the film, it is revealed that Dug had mated with another Golden Retriever (with similarities to him), and they had many puppies.

Dug's Special Mission
Dug appears in his very own short as the main character.

George & A.J.
Dug appears in this animated short as a minor character where he appears at the end and scares George and A.J.

Personality
Dug is a playful and friendly dog who is always kind. He likes almost everybody he comes across. He is also very good at following rules and can be somewhat of an airhead at times.

Quotes:
"Hi there."

"My name is Dug. I have just met you, and I love you!"

"I was hiding under your porch, because I love you. Can I stay?"

"I am a great tracker. My pack sent me on a SPECIAL MISSION all by myself! Have you seen a bird? I want to find one and I've been on the scent. I'm a great tracker. Did I mention that?"

"Oh please oh please'' be my prisoner!" (This is to Kevin, who he had been sent to catch).''

"I do not like the Cone of Shame."

"Oh boy! Oh boy! A ball! I will go get it, and then bring it back!"

"May I take your bird back to camp, as my prisoner?"

"Squirrel!" "I was hiding under your porch because I love you."

"Did you know today is my birthday? And I made a wish."

"Alpha! The rock moved!

"I will stay in the hole. I will stay in the hole. I will stay... in the- now I am going down the hole. It is very dark in the hole."

Trivia

 * In Ratatouille, as Remy runs through an apartment building, Dug's shadow can be seen on a wall. Ratatouille was released two years before Up, but Up was in production.
 * Dug has the same yelp as Scud.
 * Dug was awarded the Palm Dog Award by the British film critics as the best canine performance at Cannes Film Festival, beating out the fox from Antichrist and the black poodle from Inglourious Basterds.
 * As seen in the credits, Dug has a mate and several puppies, possibly a spoof of A Hundred and One Dalmations.