Brave Princess Merida Custom Morphing Mug-by Steel rose Material:100% ceremic The morphing mug is just plain black in color when it's cold Mug will turn white and reveal your design only when filled with a hot beverage. Just add your coffee or tea, and watch your images come to life in vibrant color You can use it as a coffee mug.he picture in the morphing mug has two sides Your favorite picture, we can customize it for you.