Morton the Elephant Bird is the son of Horton the Elephant. He first appeared in Horton Hatches The Egg. He also appeared in The Wubbulous World of Dr. Seuss and Seussical the Musical. He is the tetartagonist of the first season of The Wubbulous World of Dr. Seuss and a supporting character in the second season.
Seussical The Musical
At the end of Seussical the Musical, Morton the Elephant Bird come out of his egg. Gertrude McFuzz then offers to take care of Morton since Horton states, "He only knows Earth.". Morton's name is not revealed in the musical.