Heat Sensitive Mug, PYRUS Color Changing Coffee Magic Mug Great Gift Idea Magic: When cold, mug shows a sleeping face; When hot, mug wakes up! Considering how most people wake up cranky in the early hours, this Amazing Mug will help start off the day in a quirky and playful way. Enjoy your morning cup of coffee in a Heat Reactive Color Changing Mug. Confuse your co-workers and keep your kids distracted by placing steaming hot beverages in a mug that plays a subtle magic trick on the eyes. The perfect gift for your lovers, friends and family members.