"The Revenge of Protoboy" is the 101st episode of the series and the 12th(a) of Season 4 of Robotboy. In this episode, Protoboy returns and wants revenge to Robotboy, but after being interrupted, he decided to destroy Robotboy some other time and then Tommy and Gus must fix Robotboy before Protoboy comes back again.
In the middle of the forenoon Donnie is tossing oranges at Gus until Gus plays possum which manages to trick Donnie thinking he's unconscious (or presumably dead) which leaves Donnie running away in fear and comes to a boat. Meanwhile back at Tommy's yard Gus wakes up and explains to Robotboy what possum means and suddenly a meteor arrives and it is positioned towards Tommy and Gus but Robotboy destroys it. They're wondering how the meteor could have been positioned to them just like that until Protoboy arrives and starts to fight towards Robotboy until he gets almost destroyed and just when he was going to finish him up he gets a phone-call and flies away and tells that he will return.
Later, Tommy and Gus goes to a dessert where they need to find Moshimo's secret laboratory which they find and comes together with Moshimo to get down of the dessert where his lab is at. In the lab Moshimo, Miumiu and Tommy are fixing Robotboy while Gus watches the news where they tell that a cruise is in grave danger by Protoboy which leaves Tommy worried because his parents are on that cruise so he brings Robotboy with him to save them and the whole cruise.
At the cruise everyone is terrified by the disaster caused by Protoboy and Robotboy and his friends arrive to save them. While Robotboy and Protoboy faces each other Robotboy tries as much as he can to make his brother change his mind but Protoboy does not want to and threatens Robotboy to destroy both Tommy and the cruise. This makes Robotboy having no choice but to fight him and while they Super-activate, Robotboy gets unusually defeated quickly by Protoboy and Protoboy approaches to destroy the whole ship but suddenly Robotboy comes from nowhere leaving Protoboy surprised and Robotboy quickly reaches to his chest and removes his cables that powers him. A down-faced Robotboy looks at his brother coming to the sea and turns around to see his friend Tommy being unharmed and explained to him that he played possum like Gus taught him and they fly away.
- This episode marks the last appearance of Miumiu.
- Some fans were a little confused of what real timeline this episode really should have been shown at first. Either after the event of "Brother" or "The Old Switcharobot", especially when Tommy briefly says to Protoboy: "You were blown to bits, I saw it with my own eyes!" It might possibly take place after "The Old Switcharobot when Tommy refer to when Protoboy (inside Robotboy's body) got completely destroyed by Brainy-Yak's laser beam from his ship.
- Protoboy says: "Okay, Proto have no time to finish you, but Proto be back". This line is a possible reference to the famous line said by Arnold Schwarzenegger from the movie "The Terminator": "I'll be back.".
- The same boat from "Underwater", The Orca, is reused as the fisherman's boat.
- This is the only episode where Protoboy's deactivated mode, although funnily on his first appearance he didn't have this mode despite being shut off for a long time until Robotboy activated him again.
- Goof: When Protoboy first appeared, Gus collapsed on his back. When Protoboy left, Gus is laying facedown.
- Goof: When Protoboy was holding Tommy to show Robotboy the "Bad thing" he did, the wires on his head were missing.
- Goof: When Protoboy is first shown attacking the cruise ship, he's in Activated mode. The next time he's shown, he's in Super-activated mode.
- Protoboy is revealed to either have a girlfriend or a wife in this episode since he refers to someone as "Dear" during the phone call. This is the only episode she's ever mentioned in and she could also be the one who revives Protoboy after every episode he's supposedly destroyed in.
- According to FX designs for this episode, its production date is May 31, 2007.
- This episode's tentative title was "Return of Protoboy".
In other languages
|Int. Language||Int. Title||Translation|
|Dutch||De Wraak van Protoboy||The Revenge of Protoboy|
|French||La Vengeance de Protoboy||The Revenge of Protoboy|
|German||Protoboys Rache||Protoboys Revenge|
|Spanish||La venganza de Protoboy||The Revenge of Protoboy|