Greenman vs. Mohtles (グリーンマン対モオットレス, Gurīnman tai Moottoresu?) is the sixteenth episode of Go! Greenman.
While discussing strategies in the Underworld, Tonchiki proposes a plan to use yet another monstrous mutation. Maoh approves, and the plan is put into action. They watch as a group of small children run through a grassy area when one of them, a girl, trips and scrapes her knee. Tonchiki quickly teleports to the site and torments the girl, but the other kids begin to throw rocks at him. Following the orders given to him, Mohtles teleports as well and grabs the girl while the others are distracted with Tonchiki. However, they notice and use their Green Calls. Greenman instantly appears overhead and drops to the ground, directly in front of Mohtles. Mohtles energetically darts straight for Greenman and begins to fight. Meanwhile, Tonchiki continues after the injured girl, but he clumsily falls multiple times until being ordered back to the Underworld by Maoh. Mohtles then charges at Greenman with his head down similar to a bull. Although his horns make contact with Greenman, he is not fazed, and is able to get multiple consecutive hits off. Fearing his monster's defeat, Tonchiki orders Mohtles to grow. He disappears into a cloud of smoke and reappears larger than the houses. Greenman also grows utilizing his electronics and continues his battle. Although starting off strong, Greenman is quickly overpowered by Mohtles's strong blows. He even manages to push Greenman off a cliff. Once the hero rolls all the way to the bottom, Mohtles expels a white gas from his mouth which messes with Greenman's mind and badly damages his inner workings. Now dazed an weak, Greenman is no match for Mohtles. However, the group of children from before all band together and use the Green Calls to restore Greenman's strength. Re-energized, Greenman pushes Mohtles into a ditch and throws an Ear Boomerang at him. But before the weapon connects, Mohtles teleports higher up onto a mountain and escapes Greenman's wrath. Infuriated, Maoh orders Tonchiki to teleport there and turn Mohtles around. But, Greenman throws another Ear Boomerang, this time at Tonchiki before he can finish speaking. So, he teleports back to the Underworld to assure his safety. Albeit, Greenman finds Mohtles once more and they commence fighting once more. Greenman summons the Greenman Stick to get a few last hits before dropping it and summoning electricity to his hands by shouting "Flash Shock!" Mohtles is electrocuted and erupts into a cloud of blue smoke. However, Greenman doesn't leave without healing the injured girl's scraped knee.