The Experimental Five are a group of 5 robots created by Professor Moshimo before he created Protoboy. They originally did not work, lacked names and were failed experiments. Dr. Kamikazi would later find them hidden in Moshimo's abandoned shed where he made Protoboy, he made them work, and tried to convince them to join him, but they weren’t interested, he then sent out a clone army to capture them so he could brainwash them, though they defeated the army and escaped.
- Alpha: The leader, the smartest, the strongest and the oldest. He is pretty ruthless and hates Robotboy with a passion, not because he thinks he replaced them, but because he is envious of him.
- Beta: The most defended one. He doesn’t emote too often, but he wants to be Moshimo's strongest robot.
- Gamma: The weapons expert. He has a big ego and thinks he is the strongest robot in the world because of his large amount of weapons.
- Delta: The one who doesn't speak. He acts pretty crazy and bloodthirsty and is prone to randomly assaulting things.
- Epsilon: The closest in appearance to Robotboy. The nicest of them who does not want to harm Moshimo, but he does want to harm Robotboy because of his thought that he needs to be destroyed or else the Bay Area will suffer from the rest of the villains, he keeps this secret from the rest of them.
All of them can superactivate.