Board Thread:General Discussions/@comment-24981691-20140525033847/@comment-26302001-20150223094445

The bones in that cavern were of another Godzilla. It was confirmed by the secret files. Apparently another Muto pair in the ancient past killed it together and that female from that time buried it in that Muto made cavern and injected it with her last 2 eggs, one male and one female. Male and female adult Muto together can kill a Godzilla if they team together.