The shape of its head and mouth, kinda reminds me of goats.
It seems in the latest build the golden mount is baseline, each of the remaining 3 colorings are based on finishing each spec's artifact, but they don't just change based on spec, rather you buy it for 10k resources once you finish the corresponding artifact.
http://www.wowhead.com/news=260404/h...-and-questline
http://www.wowhead.com/news=260678/p...unts-pets-toys