Morphing Mugs Harry Potter Hogwarts Marauders Map Heat Reveal Ceramic Coffee Mug - 11 Ounces Excellent stocking stuffer idea, transformers from black when cold to reveal the Marauders Map when hot liquid is added Color changing, official Harry Potter heat sensitive ceramic mug Heat activation reveals hidden image 11 ounce in size, comes in Harry Potter branded packaging Officially licensed mug designed and printed in the USA by Trend Setters Ltd. Authentic Morphing Mugs heat sensitive mug