Moony, Wormtail, Padfoot and Prongs are proud to present…The Marauder’s Map! To everyone else, this mug appears to be blank. Add hot liquid and it will be revealed that you solemnly swear to be up to no good with the design of the Marauder’s Map! <br><br> The exterior of this officially licensed 11oz mug transforms from black as hot liquid is added, revealing the hidden image in full vivid colors. <br><br> While this mug may be used in the dishwasher or microwave, for the longest lasting, highest quality product, we strongly recommend against it.