What is "mechagodzilla"

is a mecha that first appeared in the 1974 film Godzilla vs. Mechagodzilla as an extraterrestrial villain opposing Godzilla. In subsequent iterations, Mechagodzilla is depicted as a man-made weapon designed to defend Japan from Godzilla. In all incarnations, Mechagodzilla appears as a robotic doppelgänger and arch-enemy of Godzilla, boasting a vast array of weaponry.