In season 1, Gumball's brain looks like a typical animated brain, with big dark blue eyes, eyebrows, two thin arms and legs, and a mouth. Meanwhile, in season 2, he is redesigned to look like a normal brain in "The Bumpkin." Although, in "The Others," his appearance changed for just the events of that episode.
- "The Party" (mentioned)
- "The Genius": His first physical appearance and major role. Gumball makes him smarter.
- "The Banana" (mentioned)
- "The Bumpkin": He is seen when Gumball's organs talk about the soil Gumball tries to swallow.
- "The World": His second major role. He sings "The Amazing World of Elmore."
- "The Coach": He and Gumball's other organs convince Gumball to skip going to gym class.
- "The Recipe" (cameo)
- "The Name": He appears when Gumball tries to remember that he is a loser.
- "The Vacation" (mentioned)
- "The Fraud"
- "The Question" (mentioned)
- "The Oracle" (mentioned)
- "The Others": He briefly appears when Gumball opens his mind.
- "The Vegging" (mentioned)
The Gumball Chronicles
- "The Gumball Chronicles: Vote Gumball…and Leslie?": He appears in a diagram showing his similarity to a goat brain. He appears in his season 1 design.
- Although it is Gumball's brain, Gumball was able to think without it. It also seems that Gumball is more intelligent than his own brain, as he was "training" it how to be smart.
- He appears to be much bigger in "The Bumpkin."
- A similar brain wearing a hat can be seen in "Halloween" at the house party.
- The appearance and voice of Gumball's brain has changed various times throughout the series.