The war machine Moguera was created by the Mysterians, a group of aliens from Mysteroid who embarked down to Earth looking for a place to live and reproduce following the destruction of their own world. Moguera first appeared near Mt. Fuji, devastating a town and a local shrine. The war machine then moved further up stream, sending currents of dead fish in its wake due to the tremendous heat and radiation the machine was emitting. Moguera was once again seen after a landslide in which the robot attacked a group of nearby policemen.

By night fall, the towering brute had made its way to the power plant, destroying it, before making its way into the heart of the town. Moguera destroyed the little opposition the town presented it, as the Self Defense Force deployed a battalion of soldiers equipped with machine guns and flame-throwers along with missile launcher trucks, all of which had no affect. Moguera was finally defeated, though, when a bridge the robot was crossing was dynamited, sending the war machine towering down to its own destruction.

The Mysterians deployed another Moguera later on, when the tides of the final battle were turning against their favor. The second Moguera dug its way underground, and emerged in the heat of battle. However, fate was not on its side. The war machine dug too close to a Marklite Cannon, causing it to tower over, crushing the short lived second Moguera.