

I just had a crazy theory come up in my mind.
What if, they skull crawler we see in the toys, is the actual big one they mention in K:SI
Since its back look's different colored than regular skull crawlers, it might be the true alpha.
The reason it would wake up, it would be that kong leaves skull island.
Since kong is gone, it takes his chances and wakes up from his sleep.
Put down your theories below

You might not be wrong there. I have a theory that since there was a triceratops' skull in K:SI, soooo, maybe, I don't know, Gorosaurus can also be on Skull Island?

Hello everyone, now that spoiler lockdown is gone I can finally discuss some theories and things I noticed in KotM I will say right now I am not gunna drop my theory on the plot of GvK and how the monsters get together to fight, I will drop some theories on their history together and a potential idea for the monster they may fight but I wanna focus first and foremost on the Titans themselves.
So the Titans we learned a lot about them, and a lot about the actual Universe of the Monsterverse. I wanna get right into this first and foremost with the Bioacoustics mentioned in the film as how the Kaiju can communicate across vast distances.
As we know the movie states the Kaiju can all hear the Bioacoustics and they all respond to the call of an Alpha, the Kaiju that reins over all of them, we also learned in the movie two things, Humans seem toappvalley give off a similar frequency that the creatures can understand, and Ghidorah and outsider to the planet also gives off the same Bioacoustics as the Earth-Born Kaiju which raises many questions.
I'm gunna start on this with the Kaiju themselves, not all of them respond to the Alpha Frequency that the Orca gives off, Mothra does not become subservient instead she becomes curious and calm likely picking out Godzilla's call in the frequency, Rodan also does not become subservient either if anything it merely awakens him.
Kong in the novelization also does not respond he merely ignores it and Ghidorah reacts violently thinking it a threat to his attempts to terraform the planet/the call of his ancient rival Godzilla.
This is very interesting to note since the other Kaiju immediately become docile/subservient to the Alpha or the Alpha Frequency except these 5 Kaiju. Rodan, willingly submits to the strongest creature for self preservation that's why he follows Ghidorah around he never bowed because he heard Ghidorah's call he bowed because he feared he could not win. The other Kaiju do eventually converge on Boston but before the battle is going on they aren't heading there no they just become docile, its only after the Orca is destroyed and Godzilla and Ghidorah are in their battle would they head out, to see who their new leader will be.
Why these 5 don't respond is because they are from Alpha class species, they can reject the call because their species were the dominate ones in the ancient world with the current Godzilla being the current and former Alpha with Ghidorah taking the spot of king for a brief time in KotM. Ghidorah exists outside this paradigm he is a hostile alien world destroyer coming to terraform the planet to his liking but he still can react and interact with the Bioacoustics of the other creatures, they sense him as a stranger but in a sense one of their own which is a frightening concept.
Which leads me to my next point about Ghidorah himself, and how he completely expanded this universe to new heights. Ghidorah is an alien, a powerful Kaiju from another world yet he can nestle into the ecosystem of Earth's Kaiju, this has shocking implications, the biggest being Kaiju are not native to Earth and can communicate and usurp control on other worlds. This means a lot and opens the playingfield for a ton of Alien Kaiju but also on what the Kaiju are, they are native to multiple worlds, can communicate with the same type of communication and still follow the same principles across multiple worlds there's more to them then just big Kaiju this is a setup for something down the line I feel it.
Ghidorah as well we know wants to Terraform Earth but why? What does he gain from it? Well we could say its his own dominion his own space but couldn't he do that on his own world why come to Earth? Well there are some theories I will propose.
1: Ghidorah already destroyed his homeworld and is coming to a new world to try again.
2: Ghidorah is running from something else back home he wasn't the Alpha and that's scary.
3: This links to the above theory but we know Ghidorah can absorb energy its possible he is trying to become stronger to defeat what ever is chasing him/made him leave his homeworld so as he terraforms planets he absorbs the energy.
4: Ghidorah is a Parasite.