So I was looking through the AH yesterday and picked up this item which allowed me to unlock a costume.
The unfortunate news is that this costume piece (whatever it was) is not clearly labelled in the tailor so I haven't been able to find it.
I had the notification on my screen pop up when I used it.
Does anyone know/remember what it should unlock?
If so, please link me a picture or let me know the costume name.