does not work for level 1s ... save your $30![]()
Clicking on the post "mounts" you onto an actual Nightmare Steed, and then gives you a "buff" so that whatever you mount for the next 20 min, it puts you on the Nightmare Steed instead.
I assumed incorrectly like you that the buff just changed the appearance of your mount...it in fact changes your mount.
It isn't a complete waste though as you can still place the post down...a small and expensive vanity item...but one none-the-less