This is an unused look. This appearance has never been available on a player mount.
Notes:This is one of two special Dread Raven skins that are used in Spires of Arakk and it looks much like a striking fiery version of the Dread Raven mount. While the in-game versions do not use the mount model, the skin is available for that model and we hope that it'll some day be available as a mount.
Note that this skin is intended to be accompanied by fire effects. As the effects aren't available on the regular mount model we couldn't render them here. Hopefully if this becomes a mount it will have its own special, fiery mount model.