Cursed Wander Skin is an item which will change Wander' s appearance after using it. The cursed skin is as same as Wander has in the ending scene. Dirty clothes, pale skin, darken hair and blue eyes (colossus eyes) will be his new appearance. Also, a pair of small horns and dark markings will appear on his head and his face. Besides that, this item will not give you any extra ability. However, it is a cool and memorable skin.

Dormin says the following upon retrieving the item:

That is the "Curse of the Colossus"... By using it, thou shalt resemble one in service of Dormin...