Better not ask what's inside.

Wendigo Coffin: an epic cosmetic worn on the back, from the Halloween edition.

The edition is over: merchants don't sell it any more. Whoever has it keeps it, and can sell it as a token at the auction house.

You can recolour it from the wardrobe: right-click the cosmetic, pick one of 63 colours and click the preview. It's free and you can change it whenever you like.

The token

In the wardrobe, Shift + click twice on a cosmetic you bought and it becomes a token in your inventory: sell it at the auction house or trade it. Right-click with the token in hand and the cosmetic goes back to the wardrobe.

From the same edition