A brown lobster-like monster with octopus tentacles on his hips and smaller ones for hair. He can shoot lasers from his claws. He assisted Crisis Empire when they tried to blow up Setoo Bridge. When Kotaro confronted Gazolagezola on a boat, he transformed into Kamen Rider Black RX and discovered Crisis Empire's plans during the course of the battle. As Bio Rider, he used his Bio Blade on Gazolagezola's stomach, removed the time bomb inside him, and threw it into the water. Gazolagezola went underwater and Bio Rider turned into water to follow him to shore. After getting out of Gazolagezola's trap, Bio Rider followed it and reverted to Kamen Rider Black RX. He used his RX Kick on Gazolagezola before destroying him with the Revolcane.