Wiki - Halloween Costumes
Basic Costumes can be obtained by completing a candy gathering quest for Mamma Mummy in Britain. This quest can be completed only once per year on each account, but the costumes are purchased with the special candy that acts as a reward for it, and that can be traded or sold. It is possible to get more than one costume this way if you can find someone who doesn't want one.
Double click a costume to put it on. A totem like graphic will appear on your paperdoll. To remove the costume simply take it off. While wearing a costume you will appear as your costume dictates.
Note that costumes may only be worn during the month of October.
Wearing any costume while Trick or Treating with 100 begging skill will give you a chance of special gifts instead of candy from the npcs.
Lady of the Snow
Greater Air Elemental
Greater Blood Elemental
Greater Poison Elemental
Greater Water Elemental
Molten Earth Elemental
Devourer of Souls