Unemployed Philosophers Guild When the mug is cold, the image of Bob Ross reminds you to be calm and find time in your life to create. When you pour in a hot beverage, a Bob Ross painting appears to inspire you. Officially Licensed by Bob Ross Inc. • 12 oz. Ceramic coffee cup with a comfortable handle. • All of our disappearing mugs come in a beautifully designed, colorful box. • Heat activated color changing mugs are microwave safe, but not dishwasher safe. Hand wash only. Don't soak.