How i think The false king got frozen in the ice.

Interesting theory. It's very original and creative, but I'm pretty sure (correct me if I'm wrong) that KotM director Michael Dougherty confirmed that Ghidorah really is an old rival to the Godzilla we see in the movie. Also, even though Godzilla is refered to as a "he," its gender is never really flat out cinfirmed in the Monsterverse -- not to say that I think it's female... I just think it's irrelevant.

Hard to say as its not been truly confirmed that the Godzilla is the same Titanus Gojira from Godzilla awakening. also given that Ghidorah was in the water when he was frozen, Godzilla would have been able to flat out kill the creature by triple decapitation, as Ghidorah is no match for Godzilla in the water. he may not even be able to use his Gravity beams in water due to the high conductivity of seawater which could short out his internal electric generation organs.

Interesting theory but if we analyze the Ghidorah prophecy, I think Ghidorah came to Earth and there was only ever one Ghidorah. Perhaps Ghidorah killed off the rest of the Titanus Gojira species, similar to the Skullcrawlers taking out all of Kong's species but one. But something cataclysmic must have happened, freezing Ghidorah in ice - most likely another meteor. It is rather mysterious how such a powerful super-being could get stuck in ice, if you really think about it...

Chris: i would say Muto's and their prime would more than likely be responsible for the death of most of the Titanus Gojira species. the last major Metore strike was the one that caused Antarctica to freeze so that would have been the false king. 

I have two theories:
1. Ghidorah faces Godzilla (or Dagon) and Mothra together (seen in a cave painting), but he fled to Antarida to heal his injuries, but when he was at rest he froze.
2. Godzilla attacked Ghidrah by surprise in the South Sea to Antarctica (as we saw on KOTM) to drown him, but he just passed out and Godzilla left him for dead, leaving him there to freeze.

But like you, I consider that Ghidorah did not arrive 66 million years ago, but when the first human beings already existed.