Mother's Day Gift Mug - Funny Novelty Grandma Mug, Best Grandma Ever Color Changing Mug Morphing Coffee Mug Cup, Awesome Gift Mug for Grandma Holds 11 Ounce Magic Heat Sensitive: Just plain black in color when it's cold,mug will turn white and reveal Design only when filled with a hot beverage New design, novelty, funny Sturdy and durable Awesome Gift Idea