Mechagodzilla (GvMG)

The first Mechagodzilla was created as a weapon of destruction by a race of ape-like aliens, sometimes known as Simeons or the Black Hole aliens(See: Alien races from the Godzilla films).

It first appeared in a pseudo-flesh outer covering, masquerading as the real Godzilla during attacks against Japan in Godzilla vs. Mechagodzilla. Curiously, while the Simeons gave Mechagodzilla a flamethrower in his mouth to mimic Godzilla's atomic beam, they didn't bother replicating Godzilla's unique roar. Godzilla's dinosaur friend Anguirus wasn't fooled by the impostor. Their battle went badly for Anguirus, but tipped humanity off to the charade.

Soon the true Godzilla appeared and exposed his rival's metallic form completely. Interestingly, after losing its disguise, Mechagodzilla's fingers lost all mobility. (No explanation for this was ever given.) The battle resulted in a tie, however, and in the end it took the combined might of Godzilla and King Caesar to remove Mechagodzilla's head from its shoulders, ending the threat.

The Simeons rebuilt their dreadnought for another try in Terror of Mechagodzilla one year later. Having learned the value of teamwork firsthand, the Simeons called in an old debt to pair Mechagodzilla with the aquatic dinosaur Titanosaurus. (Any reasoning as to why they did not bother to recruit Titanosaurus in the first film is never mentioned, though they may have simply thought that Mechagodzilla was more than a match for Godzilla in the first place, making the extra help unnecessary.)

This time, there were some modifications to it, including moving Mechagodzilla's brain down into its neck so it could function unimpaired with its head completely removed. Godzilla's perseverance combined with the timely self-sacrifice of Mechagodzilla's operator brought the machine down for good. The King of the Monsters buried Mechagodzilla's shattered form deep underground to prevent another repair job, and since this was the final film of the original Godzilla series, he was successful.

Arsenal
Showa Mechagodzilla has armour constructed out of a mysterious alloy known as "Space Titanium." It is also equipped with a staggering amount of firepower.

Mechagodzilla is capable of firing a rainbow coloured optical laser that seems to be equal in power to Godzilla's atomic breath- its head can rotate 360 degrees, allowing the robotic reptile to shoot down an opponent that might attempt to approach from behind. Spinning its head at high speed allows Mechagodzilla to raise a forcefield. When disguised as Godzilla, MG could fire a heat ray from his mouth. Curiously, after the disguise was destroyed, MG never used the heat ray again.

Showa MG is also equipped with powerful missiles in its fingers, knees, mouth, and even its toes. These missiles can explode on contact with a target, or they may lodge in the flesh of an enemy like darts. Located under a hatch in MG's chest is a weapon that fires a jagged orange energy beam with enough slicing power to cut a mountain in half. Showa Mechagodzilla is no slouch in close combat either, as evidenced in its combat against King Caesar, and finally, Mechagodzilla can fly via rockets in its feet a back.

Trivia
The original Mechagodzilla is the only one to be referred to by numerics within the movies themselves. When it is rebuilt in its second appearance, the "MG" emblazoned on its arm has a "2" added to it. It is still always referred to as simply "Mechagodzilla"; none of the versions are actually given numbers by the characters in the movie, since none of them share the same continuity.