Review on The Unemployed Philosophers Guild Heat Reactive Constellation Mug - Reveal 11 Constellations with Coffee or Tea - Presented in a Playful Gift Box by Brad Fleming

So we're already on the third cup, because it's easy to forget that you can't wash it in the dishwasher. A run in the washing machine destroys the outer layer, which is a heat-sensitive sticker on a plain black mug. Heat sensitive to display and of course destroy the constellations. When we got the third the sticker around the edge had come off with nothing just new out of the box. That being said, the mug needs a certain temperature to reveal the Zodiacs as advertised. Too much (boiling 210F) and the whole sticker will turn gray. (See image.) Too little (120F from the tap) and nothing happens. To put it mildly, I'm not happy.