Review on The Unemployed Philosophers Guild Disappearing Dino Mug - Color Changing Coffee Mug for Dinosaur Lovers - Heat Sensitive - Watch Dinosaurs Transform into Fossils! by Nate Jenkins

Obviously you buy this mug for the heat sensitive aspect of the design and it works great. My co-workers love watching dinosaur skins disappear and skeletons having fun, so it's a great conversation starter. Another added benefit of the heat-sensitive design is that you can visually tell if your coffee is cold. It should be noted that this is a wide mug and will not fit in a regular mug warmer. Instead, I use a wider candle warmer. The mug is ceramic so if you drop it it won't fall. Unfortunately I tested it myself and the mug actually broke in two when I dropped it, but I love this mug so much I've bought it again.