I Solemnly Swear That I am Up To No Good Harry Potter- Funny Magic Morphing Mug 11oz Coffee Mugs or Tea Cup Cool Birthday/christmas Gifts for Men,women,him,boys and Girls Magic Morphing Mug is Black when cool and turns white to reveal artwork when warm. Holds 11 ounces of your favorite beverage. Simply pour in any hot liquid to see the transformation and artwork revealed! Microwave safe but hand wash due to the nature of the morph coating. Printed using premium ceramic, non-toxic, industry leading dye sublimation technology. Dyes the mug with the image to ensure permanence in color and design so it lasts for a long time. Perfect gift for under $20. Image is printed on both sides so it doesn't matter which hand you drink from. 100% satisfaction guaranteed