Yertle made his debut in Yertle the Turtle by Dr. Seuss, he appears as king of the pond. Dissatisfied with the stone that serves as his throne, he commands the other turtles to stack themselves beneath him so that he can see further and expand his kingdom. However, the stacked turtles are in pain and Mack, the turtle at the very bottom of the pile, is suffering the most. Mack asks Yertle for a respite, but Yertle just tells him to be quiet. Then Yertle decides to expand his kingdom and commands more and more turtles to add to his throne. Mack makes a second request for a respite because the increased weight is now causing extreme pain to the turtles at the bottom of the pile, as well as hunger. Again, Yertle yells at Mack to shut up. Then Yertle notices the moon rising above him as the night approaches. Furious that something "dares to be higher than Yertle the King", he decides to call for even more turtles in an attempt to rise above it. However, before he can give the command, Mack decides he has had enough. He burps, which takes away Yertle's throne and tosses the turtle king off the turtle stack and into the mud, leaving him "King of the Mud" and freeing the others.
The Wubbulous World of Dr. SeussYertle appears in this series as an antagonist. He is portrayed as a sleazy con artist who tries to deceive people into doing his bidding and making him their kings, but the protagonists always foiled his plans. The character retained much of his egotism and lust for power in the series, sans his original royal status, but his inevitable comeuppance and occasional insecurity lent him a sympathetic side.
His most villainous role was in the episode, Horton Has A Hit. In that episode, he cons Horton the Elephant into becoming a rock star, with him as his manager. He also convinces Horton to leave his son, Morton the Elephant Bird behind. He even tried to prevent the two from ever contacting each other in any way and even paid some kids in the jungle to hang out with Morton. At the end of the episode, he tries to become a star himself, but the people just end up throwing things at him.