Well, I found that on this pack: http://www.minecraftforum.net/topic/220918-16x151-wayukian-pack-horse-color-and-pattern-previews-on-pg125-500k-downloads/ a certain zombie skin only shows up on a beach biome. I've looked around for how to apply this(using Randomobs) but cannot find anything even MENTIONING these kind of settings! Could anyone help me, as I may use this on my new texture pack?