Greenman vs. Red Rock (グリーンマン対レッドロック, Gurīnman tai Reddo Rokku?) is the thirtieth episode of Go! Greenman.
Reassuring his master as usual, Tonchiki transforms a nearby minion into Red Rock and explains the monster to Maoh. Impressed with the monster creation, Maoh allows it to be released. On the surface, a group of children are seen playing with a ball which rolls away from them. As one of the children chases after it, the ball leaps into the air and explodes into a cloud of smoke, revealing Red Rock. Three of the children run far away, leaving the fourth behind. As Red Rock engulfs him in red smoke, the boy activates a Green Call. Greenman soon after appears and battles Red Rock who is easily beaten down. As Red Rock lay on its back squirming, Tonchiki forces it to grow. Greenman alters his own size to match Red Rock's and they fight in a small town, gradually making their way up a mountain. Once again, Red Rock is easily outmatched, until the monster begins spitting red mist which falls to the ground and hardens around Greenman's feet. Now immobilized, Greenman is much easier to inflict damage upon. However, Greenman tries his hardest to defend himself, even managing to flip Red Rock off the mountain. As Red Rock continues to clobber Greenman, the hero's circuitry is greatly damaged. The children, closely watching the battle unfold, realize what is happening and one of them uses their Green Call. Repaired, Greenman summons the Greenman Stick and firmly plants it in the red goop which is instantly sopped up. Mobile once more, Greenman attacks Red Rock with the weapon until Maoh suddenly grants him with the ability to teleport. Red Rock teleports behind Greenman and tries to trap him once more, but the Greenman Stick's beam stops the flow of smoke. Greenman then discards his weapon and fires a Mouth Beam at Red Rock, causing him to combust.