As soon as the black light images hit the web speculation has been crazy as to what the creature is in the NYCC Kong: Skull Island poster.
At first some stated they thought it was some type of sea creature like an eel (hints at King Kong Escapes) but a clearer full poster view has led to even more thoughts.
Some have suggested it looks like a Pliosaur or a Mosasaur, both have long slim mouths like the image but we know there will be dinosaurs in the film, it's almost a given, so why put a random one in the poster.
We believe fans are looking in the wrong direction, they are looking at sea base dinos but the fact that the image seems to be covering the island and is far to big to be actual size we believe it's something else.
One must remember Kong is part of the same universe as Godzilla and it was announced shortly after Godzilla came out in 2014 that they had rights to other Toho monsters, Rodan, Mothra, and Ghidorah.
Rodan could certainly fit the bill to help bridge the crossover from Kong to Godzilla being a dinosaur based character much like Godzilla. The image definitely fits Rodan in a number of ways the beak, possible wings, that it suggests it could be flying over the island, among other things. Yes this is speculation but when you look at some fans concepts for what the Legendary versions of the Toho monsters will look like, it is not such a far stretch . We will see if this or other speculation pans out, till then my money is on Rodan.