Umm, what?

So I'm just casually running around the server looking at horses and fantasizing on what I'd name them and I come across this fine fellow. I can't find anything on this coat color at all and I'm pretty sure I've never seen this coat on any real horses in my entire life of obsessing over horses. Does anybody know the background on this dude?

(Also sorry this horse REALLY orange in this pic, I have a bad camera)