Aspect of Alkosh

The Aspect of Alkosh is a giant golden dragon that can be seen in the distance in the Spilled Sand illusion created by the Mask of Alkosh during The Dragonguard quest.

There is no way to interact with him or even get close during normal gameplay so this model is intentionally unfinished and has no official name. It is also possible that this is only meant to be a statue rather than a living dragon.