Review on 🗺️ Harry Potter Marauders Map - I Solemnly Swear - 16 oz Large Ceramic Morphing Mugs – Heat Sensitive Clue Mug - Full Image Revealed with HOT Liquid by Darryel Tokarczyk

The writing is somewhat visible when the mug is warm. Since I ordered this in winter, it is mostly visible in cold ambient temperatures. But I see that it works by pouring hot water (sort of in reverse). I also ordered a black mug that reveals when hot liquid is added. The black cup is a lot harder to see when it's supposed to be invisible, and I'd recommend it unless you really want to use it for icy liquids. Gave this and the black mugs to the Harry Potter fanatics in my family and they loved it. Note: The one I received from the first seller was chipped inside at the bottom. I sent it back and had to buy it from another seller as the first one was out of stock. The second was not injured.