So Has Anyone Figured Out Who This Monster Is?

Maybe a different type of muto

Its the splash from the first jet crashing, it takes a while for the water to splash that high

I agree with Mercus. Definetly a different kind of muto because I don't recall Gareth saying there will be another kind of monster

However the longer I stare at it, it begins to look like toothless from how to train your dragon

@ Wolfguy & Panthalassan

I think they just timed the splash with him rising to try and mask it.  If you rewatch the trailer, especially in slowmo, it looks like he rises from behind the clouds/smoke.  He also seems to cut through it, where the jet is clearly in front of it.  There's also the fact that the splash is white, while he is darker in color.

That is definitely something. Maybe the Mutos have the ability to extend their necks? So, maybe the Winged Muto extends his neck for Aerodynamics?

It's just the splash from the first plane that goes down just to the left of the screen. This pic was taken at a very good time, but it's just water contrasting against the grey fog.

It's not a monster at all.

If you don't believe me, watch the trailer again and keep your eyes on the splash the first plane produces. It's just water guys, and the proof is that it dissipates and disappears almost immediately.

It's not a monster at all.

Actually guys, that is a monster! Rewatch the scene, the wings are actually flapping down! I just took a look and I was skeptical, but after analyzing it, it is actually a flying monster!

@ tw_g-fan2014

It doesn't look like it dissipates to me.  More like it goes back behind the clouds.  I also don't see why it would be the only part of the splash that's that dark, when the entire splash is in front of the clouds.

Its a splash, Rodan's not in it and he has gills

Oh wait- yeah, that's just a splash. My excitment blinded me there. :P