Mechagodzilla

Ready Player One
In Ready Player One, Mechagodzilla looks like an updated design of Mechagodzilla's original Showa look, with an angular snout, nostrils, red eyes, and the odd fin shape on his head. His dorsal plates are triangular and sharp, and his hands are rather large.

Godzilla VS Mechagodzilla
Mechagodzilla is a very accurate recreation of Godzilla using metal plates. His eyes are a fiery orange color, and he has a large hole in his chest that is the same color. His dorsal plates are more symmetrical and angular than his organic counterpart.

Godzilla VS Mechagodzilla
Mechagodzilla's roar sounds like a metallic copy of the real Godzilla's roar.

Ready Player One
In RP1, Mechagodzilla's roars are genaric moans and groans that sound slightly similar to some of Godzilla's original roars.

Godzilla VS Mechagodzilla
Before he is taken over by the Xiliens, Mechagodzilla has no personality. Once he is taken over by the Xiliens, however, he seems to take on his own personality, becoming slightly like King Ghidorah, since he was build using some of Mecha-King Ghidorah's parts. He angrily attacks Godzilla relentlessly, having no stamina, but sometimes disobeys orders to retreat after being damaged, which causes him to require multiple repair jobs, and eventually leads to his defeat.

Ready Player One
In Ready Player One, Mechagodzilla acts very sinister, almost grinning at sometimes when he's fighting the Iron Giant and chasing the two main characters. He sometimes even winces in pain when Gundam slices him with his sword.

Ready Player One
a Mechagodzilla drone is deployed in Ready Player One to attack the main characters, and gets into a fierce but short battle with both the Iron Giant and Gundam. the Iron Giant only succeeds in angering Mechagodzilla, dealing minor damage. Gundam, however, manages to Injure Mechagodzilla multiple times, slicing him in the chest, shoulder, and mouth. In the end of the fight, Mechagodzilla's eye is shot, and one of the main characters throws a grenade into his head, which explodes, killing him.

Godzilla VS Biollante
In one of the interlude chapters, the Xiliens obtain blueprints for Mechagodzilla from Ready Player One using their access to the multiverse. they succeed in building Mechagodzilla, which is why, when they are controlling the human's Mechagodzilla, they refer to him as "Kiryu" instead of "Mechagodzilla" because they already have their own Mechagodzilla.