The Yak in the Sack is a whimsical and musical yak who's determined to make the world as nice, safe and fair as it can be. He hails from Fair Town, where the population plays fair games.
The Yak in the Sack always attempts to maintain a cheery and optimistic demeanor, but this facade of his gets weighed on when somebody fails to follow his nice, safe and fair ways. He's shown himself to not be beneath anger and name-calling, as he occasionally insults those who disobey him under his breath, and he even gets downright threatening if pushed too far.
His musical side tends to annoy those around him, as he puts his ideas and thoughts in the form of a song constantly. Even without a melody equipped, he continues to rhyme each sentence, no matter how frustrated he gets. He's very controlling and manipulative, though he simply wants the land to be equally fair to everyone, and for everyone to be happy. He sometimes does the wrong thing for the right reason, such as tattling Norbert's hiding spot to the clueless Dag in a game of hide-and-go-seek. He eventually does, however, unite the beaver brothers in fairness, although it was in a game against the Yak.
He's a tall, pistachio-colored yak who inhabits a pale rose sack with the word "SAK" written on it in red. He wears a floppy hat of the same color of his sack, which his loopy white antlers branch out from, he wears white gloves on his hands, and an amaranth bow-tie around his neck. He also carries his trusty magic fuzzy wand that warps objects into lively, friendly creatures.
Norbert and Daggett refer to him as a "phony Shakespeare".
The beaver brothers made up a game involving him named "Kick the Sack".
His mythical world and outlandish fashion is Micah Wright's homage to the world of Theodore Seuss Geisel.