"MUTO" is an acronym for "Massive Unidentified Terrestrial Organism".

Is Muto prime dead?

While its shell can protect it from most damage, Godzilla's blunt-force attacks can damage MUTO Prime's armor, and his atomic breath does indeed hurt it, even though it can't knock it out. MUTO Prime is finally killed when Godzilla stomps on and crushes its head while it is helpless after being knocked onto its back.

What does Godzilla stand for?

Godzilla's name is a transliteration of Gojira (ゴジラ), a combination of two Japanese words: gorira (ゴリラ), meaning "gorilla", and kujira (鯨 or クジラ), meaning "whale"