The Mysterians and Godzilla vs. Spacegodzilla
In The Mysterians, Moguera is a robot used by the Mysterians to assist in destroying humanity to make them bend to their will and supply them with a sufficient amount of land and women. It attacked a small village with its eye beams, and proved immune to machinegun fire, flamethrowers, and mortar rounds. It was destroyed when the bridge it was standing on collapsed due to the military dynamiting it.
A second Moguera appeared as Markalite beam cannons assaulted the Mysterians' base. This Moguera tried to destroy one of the Markalites by burrowing underneath it, but the weapon fell on top of it, crushing and destroying the short-lived second Moguera.
In Godzilla vs. SpaceGodzilla, M.O.G.U.E.R.A (Mobile Operation Godzilla Universal Expert Robot Aero-Type) was a UN-built mecha designed to fight Godzilla following the failure of G-Force's Mechagodzilla.
Mogera has an expansive arsenal of weapons. The most heavily-utilized and standard weapon are the plasma laser cannons built into its eyes, which rapidly fire yellow plasma shots. A drill bit is located in the center of its face, which can be used for close range fighting. It's cone-shaped hands are capable of releasing blue energy beams, known as autolasers. Furthermore, the hands can open up and launch spiral grenade missiles. Its chest secretly conceals a plasma maser cannon, a powerful energy weapon. It can fly through earth's atmosphere at Mach 1 and through space at Mach 44. It is also capable of moving on land via independent leg action, or with the treads built into its feet and legs. Moguera is the aggregate form of two vehicles: Land Mogera, a tracked armoured fighting vehicle able to drill through the earth; and Star Falcon, a VTOL craft capable of space flight.
Originally, Godzilla was planned to battle Spacegodzilla and a second Mechagodzilla, but it was thought it'd be too onesided for Godzilla to face the same robotic twin that very nearly killed him the year before, so the weaker Moguera was revived as an ally to Godzilla.
In the ending credits of Godzilla: Final Wars, we see a boy playing with Godzilla plastic-designed figures; one certain figure among the toys was Moguera from the Showa series.
It appeared in one of the Toho website non-commercial cartoons, Retro Moguera, directed by Miles Rilehoff.
Moguera appeared in the TV show Godzilla Island (1997-1998), and was known as "Proto-Moguera". In the "Proto-Moguera Saga", the machine is taken over by the series' villianess and used to fight Godzilla in a bizarre Whack-A-Mole-type conflict.
Ironically, Moguera's name is derived from the term Mogura meaning "mole" since it is a robot that is not only used for combat, but for digging purposes as well.
Moguera was the first robot monster in the Toho universe.
As the purpose for M.O.G.U.E.R.A.'s construction was to do what Mechagodzilla had come so close to doing, killing Godzilla, it is quite possible that M.O.G.U.E.R.A. was, or was going to be, outfitted with a G-Crusher system like Mechagodzilla's. Without one, M.O.G.U.E.R.A. would be no more useful against Godzilla then Mechagodzilla was before it was outfitted with it's G-Crusher. However the Spiral Grenade Missiles that are equipped to M.O.G.U.E.R.A. could possibly have been made to preform the same function, as they clearly have the power to penetrate a kaiju's hide when they demolished Spacegodzilla's shoulder crystals.
In a strange way, M.O.G.U.E.R.A. could be considered the "grand-child" of Mecha-King Ghidorah, as it was constructed from the wreckage of Mechagodzilla, who was himself constructed from Mecha-King Ghidorah's wreckage.