Board Thread:MHX General Discussion/@comment-4969421-20151109154146/@comment-5569775-20151201021216

Well, seeing the actual fight and the second stage, I agree with pretty much everything you said Narga.

Though I don't think it's the skulls themselves giving him the different elements per se, as the attacks are still coming from the opening on the tip of the tentacles, thus from inside him. It's possible that while it's swimming around in the bones(before becoming enraged) it's eating the bones, specifically the marrow of them, which apparently can, depending on the monsters, contain some of their element. The blue spots on it's body could be sensory glands that allow it to find the bones of specific elements when switching skulls or when searching for bones of a certain element.