|“||My dad eats trespassers.||„|
|~ Tina Rex warning Gumball, Darwin and Anais about her father, right before he makes his first appearance on the show.|
- The Quest: A known villainous act he does is eating Trespassers, that makes him a known murderer on the show.
- The Fight: Before he has a talk with Nicole, he makes an evil grin. Despite his immense size, he was beaten up by Nicole.
- The Routine: The first episode in which his entire body is in view. He is guarding a mountain of stolen groceries in the Junkyard, where Richard is trying to get mayonnaise. They then get into a fight.
Mr. Rex is a large tyrannosaurus with green eyes who has a scar across his left eye. He is also blinded in his left eye.
- Mr. Rex was originally going to have his first major role and full-body appearance in the scrapped episode, The Rex, which was scraped due to the budget being too expensive; but then, in The Routine his actual appearance was revealed.
- In The Fight, Mr. Rex was shown to have two regular eyes and in The Routine he is blinded in one eye. It is unknown how he got blinded but it could be possible that he got blinded and scarred after he got beat up by Nicole.