King ghidorah vs Mechgodzilla
King Ghidorah was originally created by the Garogans and was given to the Xiliens who sent Ghidorah to attack earth for the first time in the showa series. Xiliens were completely unaware of earths kaiju even so King Ghidorah put up one hell of a fight as it took the combined strength of Godzilla, Rodan, and Mothra, to repel the golden dragon from earth.
Mechagodzilla the mechanical copy of the king of the monsters himself. Originally created by the simians who sent him to attack earth disguised as Godzilla. The simians equipped Mechagodzilla with a flamethrower to mimic the kings atomic breath. As Mechagodzilla passed through japan it came across Anguirus. Confused at seeing what he thought was his fellow kaiju Anguirus was quickly overpowered and severely injured as Mechagodzilla broke his lower jaw. Anguirus quickly retreated before he could be hurt any more.