Wolves and musk ox face off on the Arctic tundra. As the mug changes, more wolves come out of the woods and a spectacular display of Northern Lights – the Aurora Borealis – appears in the sky. Wonder mugs are color-changing coffee mugs that change dramatically when a hot beverage is added. If you're looking for a unique gift for them, what a unique way to remind them of you daily! These unique, high quality gift mugs utilize color-changing or “thermochromatic” ink that changes color when hot beverages are poured into the inside of the mug. Color change gift mugs are ideal for fund raisers, birthday gifts, teacher's gifts, corporate gifts and more. All mugs are microwaveable. We recommend hand wash only to preserve the magic Wondermug ink.