When you add hot water, Captain Kirk, Mr. Spock, Lieutenant Uhura, and Dr. McCoy leave the Transporter Room on one side of the mug and materialize to explore the planet surface on the other side of the mug. Energize! Perfect for any hot beverage: coffee, tea, hot chocolate, pumpkin spiced beverage. • 14 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. • UPG is a novelty gift company specializing in smart and funny gifts. Check out our shop for all types of quirky fun stuff! Timeless Keepsakes~ Trendy Kitsch~ We Have It All