Not your average coffee mug, this one is covered with heat-sensitive materials on the outside. As it’s filled with hot coffee or liquids, the black-colored mug magically turns on.

At first glance it’s simply a standard black mug with big white letters that say “OFF”. Nothing fancy, but once you add the hot beverage of your choice, the mug changes color to white and in big black letters it states: “ON”.

[via ToxelWishingfish]