Treasures of the Lost are mystery bag packages that can be purchased from Tess during the Festival of the Lost.
Cost: 300 Silver for 1 bag, 500 Silver for 3 bags, 900 Silver for 6 bags
Guaranteed reward: 1 random Legendary Mask
Possible rewards: 1 Paper Glue, 1 Jackolyte, 1 Flight of Shadows, 1 Skull Mask, 2 random Festival Candy, 1 Paper Scraps