Ego debuted in the episode "All About Ego". Like the comics, he is a living planet that has the ability to control its own surface. He can create cannon, fissures and many challenging problems for any hero on his surface. But in the center of Ego is his true form - a miniature version of Ego who is the heart of the planet. He has a big mouth and acts similar to the Red Hulk. Later on, he returns as an ally to the Hulks, and allows them to pilot his planet body in "Planet Monster" during the battle against the Supreme Intelligence and Kree.
Ego was alluded to several times throughout the film as Peter Quill's real father, but his name was not directly stated. He was the one who hired the Ravagers led by Yondu Udonta to bring his son to him following the death of Peter's mother. However, Yondu instead trained Peter Quill to be a Ravager and did not tell Peter of his true heritage.