The first Mechagodzilla (メカゴジラ, 'Mechagojira') was created as a weapon of destruction by a race of ape-like aliens (sometimes known as Simians), from the third planet from a black hole. He first appears in Godzilla vs. Mechagodzilla and Terror of Mechagodzilla.
Mechagodzilla first appeared in a pseudo-flesh outer covering, masquerading as the real Godzilla during attacks against Japan. Curiously, while the Simians gave Mechagodzilla a flamethrower located in his mouth in order to mimic Godzilla's signature Atomic Breath, they didn't bother replicating Godzilla's unique roar. Godzilla's ally Anguirus wasn't fooled by the impostor, and attacked. The battle went badly for Anguirus, whose lower jaw was broken in the process, forcing the Kaiju to retreat. But the battle tipped humanity off to the charade. Soon the true Godzilla appeared and burned off his rival's disguise. Interestingly, after losing his disguise, Mechagodzilla's fingers lost all mobility (probably due to suit limitations). The revealed Mechagodzilla then overwhelmed Godzilla, but was called back for repairs because of the damage Godzilla inflicted on him.