Greenman vs. Tsunojiras (グリーンマン対ツノジラス, Gurīnman tai Tsunojirasu?) is the sixth episode of Go! Greenman.
The episode starts with Maoh ordering Tonchiki to create another monster to get the blood of children. So, Tonchiki complies and mutates a Minion of Maoh into Tsunojiras, who is deployed with his creator near the children. Tsunojiras creates a large, spiky, ball and rolls it down a hill to the children. The kids quickly run over to the object, curious about what it is and where it came from. They begin pulling the spines out of it, but a black noxious smoke begins pouring out of the holes where the spines once were. This gas causes the children to pass out on the hill; Tonchiki and Tsunojiras then step in to view, and report back to Maoh. Tsunojiras then picks up one of the kids, but unfortunately for the monster, a Green Call falls from the child's pocket and activates, summoning Greenman. Greenman immediately appears, and re-awakens the children before beginning to fight with Tsunojiras. After a thorough beat-down from the hero, Tsunojiras is made giant by Tonchiki, at the request of his master. Now giant sized and fighting in a small town, Tsunojiras begins to exhale a similar black smoke to the one that previously seeped out of the spined ball. The gas causes Greenman to drop to the ground, now weakened. Luckily, the children used the Green Calls to strengthen their hero once more. Greenman stood right back up, and leapt at Tsunojiras, knocked him to the ground. The two fought vigorously, but Tsunojiras's efforts weren't good enough. So, to enhance his performance, Tonchiki summoned one of the spikes balls directly on the monster's forehead. This now allowed Tsunojiras to fire explosives quills from his head, as well as use the ball as a ramming device. This unexpected trump card quickly overpowered Greenman, so the children used the Green Call for a second time, this time shooting a laser beam at Greenman's body, strengthening him even more. Now with another sudden burst of strength, Greenman shot an Ear Boomerang at the ball, and destroyed Tsunojiras with the Breaster attack.