Flowing script of your character's native tongue creates the following message:
Letter wrote: "Dear [insert suffix and name],
It is with great pleasure that you have been invited to a fancy dress party at the Brackenridge Manor house in the forest outside of Domino. Festivities will include games of chance, music, and a banquet all to celebrate All Hallows Eve!
No need to reply to this message. Your attendance is assumed, however you need not attend if you so desire. Your costume will be proof of your invitation. Any guest who arrives without their issued costume will be barred from entry. See the attached card for [date, time, and directions].
Dr. V. S., PhD. M.S."
Inside the box is a mask, cape, and a few other pieces that come together to create a tasteful minimalist interpretation of that characters powers or racial heritage.