
One of the main things that caught my attention in the second KOTM trailer right off was the 2nd new Titan, the mysterious moving mountain. A lot of people jumped on Anguirus immediately, but I always take 'inside info' with a can of salt. Some say Baragon, others that mountain Kaiju from the Monsterverse comic. It wasn't til I listened to the trailer with a good pair of headphones that I heard the ambient background noise of the scene: the monster's roar. Certainly a familiar sound! It is lower-pitched, and guttural but nonetheless unmistakably Anguirus-esque. You can also see the horn on his head, and just as it cuts to the next clip, the horn on his nose. If I wasn't excited before (I was) I sure am now! the sound is at the 0:56-0:57 mark. Tell me what you think!

I really want the monster to be anguirus but I just don’t see it happening

Its probably just an OC Kaiju. I think there will be a montage of Kaiju emerging at the end of the movie to leave the audience with an impression of a greater threat to come.
However, if it is a Toho monster, it is more likely Baragon. Baragon also has a horn on his nose, and is well-known for burrowing under the Earth. Baragon is also far more popular than Anguirus in Japan so it could be a little Easter egg for fans over there.

But Anguirus is arguably more popular over here in 'Murica, and it is an american film, directed by an American Godzilla fan. 'Sides that, that roar ain't Baragon.