"Gus's Big Mouth" is the 79th episode of the series and the 1st(a) of Season 4 of Robotboy. In this episode, when Gus has a very bad breath, Tommy and Robotboy take him to the dentist to clean his teeth.Unfortunately, the dentist happens to be Felonious Hexx, and gives Gus golden teeth which will make him say undesirable things to many different people.
Felonious Hexx: Tough break, boys. I was on your side. Maybe... *magic teeth glow* Maybe if your weren't so busy being stupid, muscle bound, lazy, boring, untalented, badly dressed fowl smelling, and just plan butt ugly, you would've gotten him! Um.... Excuse me, I have to...GO AND FEED THE FISH!
- The last appearances of Kurt, Stu, Mookie and Bambi in the entire series
- Goof: When Robotboy punches the golden teeth out of Gus's mouth and they are end up in Felonious's mouth, Gus and Tommy are laughing at him. But when Gus closes his mouth and stops, Tommy is still laughing with his mouth open, but we can hear Rupert Degas in his Gus voice laughing instead of Tommy's voice.
- The one criminal from "Foot Brawl" shows up again as one of the contestants for the tough guy contest.
- Robotboy, for some reason, is freely moving around in public with Tommy and Gus instead of being hidden in Tommy's backpack. Tommy nor Gus seem concerned about keeping him a secret in this episode. The same happens in "Ogbot".
- Robotboy is heard doing a very human thing off screen: throwing up after he smelled Gus' bad breath. It sounded like he was throwing up small, metallic objects like nuts and bolts. This was very odd, but very funny to see.
- Hexx's assistant was either a rabbit-turned-human or a human-turned-rabbit. Though, it could be assumed it was the latter since she probably worked at the dentist's office before Hexx was hired there. She became a rabbit because she tried to do magic by pulling a clipboard from behind Hexx's ear, which he clearly did not find amusing.
In other languages
|Int. Language||Int. Title||Translation|
|Dutch||Gus en zijn grote mond||Gus and his big mouth|
|French||Des Dents enragées||Enraged Teeth|
|German||Das große Maul||The big mouth|
|Spanish||Boca grande de Gus||Gus's Big Mouth|