With the release of the patch 6.1, a new, rare mount has been added to World of Warcraft – the “Void Talon of the Dark Star”.
Basically, it’s quite simple to obtain the “Void Talon of the Dark Star”. You just need to enter a portal that takes you to the “Edge of Reality”. Once there, click on an egg and you will receive the mount. There are no fights or anything else to contest. By the way, the portals look like this:

And they present only a minor problem. They remain up for a few minutes and despawn as soon as someone uses them. They are also primarily located near the Apexis daily quests. You can click on the portals as long as you do not have the mount yet or if you are in a group.
There’s only one catch: The portals are incredibly rare, and when they open, it’s likely in a crowded area because everyone is doing dailies there. So you need an immense amount of luck to get to them.
But in a few years, when no one is lingering in Draenor anymore, this problem will be solved. So good luck on your search.
Here are the known spawn points:

And this is what it looks like when you are lucky: