Greenman vs. Lorbabla (グリーンマン対ローバブラ, Gurīnman tai Rōbabura?) is the twenty-eighth episode of Go! Greenman.
The episode starts with Maoh and Tonchiki having a short conversation that ends with Tonchiki falling to the ground. Meanwhile, 3 boys and a girl are playing a cowboy game with toy guns and a lasso. One of the boys throws the lasso towards his friend, but he is instead caught by a different rope. With a heavy rope gripped in his claw, there stood Lorbabla, Tonchiki's most recent monster mutation. He reels the boy in and holds him firmly to his chest. Tonchiki also teleports to the scene and chases the remaining three children who activate their Green Calls. Greenman appears before Lorbabla who throws the roped child off to the side. Whilst Greenman is occupied, Tonchiki chases after the child from earlier, who is still stuck in rope. But, the rope ends up tripping Tonchiki, and the boy runs further away. Lorbabla continues to fight hard but is rolled down a hill and throws his rope at Greenman. But Greenman catches it, and the two initiate a "tug of war". Seeing an opportunity, Tonchiki splits the Earth open between them, and Lorbabla manages to pull Greenman in. Once finished falling down the hole, it is revealed that it led to the Underworld! Greenman attempts to grow, but his electronics fail, leaving him completely trapped underground. As the hero struggles to fight, he is beaten on by nearly everyone present including Maoh himself. Greenman continues to fight back even trying to use a Leg Arrow, but it once again fails and Maoh drops rocks on him. On the surface, the children can hear what's happening but Tonchiki teleports there to torment them. As imminent defeat becomes more and more apparent, the children band together and use their Green Calls. In a burst of energy, Greenman jumps straight up through the ground and onto the surface with Lorbabla following. They engage in a short battle until Tonchiki forces Lorbabla to grow. Greenman also alters his size utilizing the machinery within him and easily defeats Lorbabla with a series of attacks, finishing him off with a Ear Boomerang.