I guess someone beat me to it since collector wasn't working on Test :( lol
The item it summons now is this:
https://everquest.allakhazam.com/db/item.html?item=111837
When you click Ghostrider's Bridle it will summon that item onto your cursor if you don't already have it. You can still use the mount on Ghostrider's Bridle as well, it simply puts the new skeletal horse on your cursor.
-Rainbow Dash