To be honest, this Tetris mug would probably drive me crazy. I would fill it with my morning coffee and then wait for that one long piece to fall. And I'd be waiting forever, because it never, ever will.
But the board will vanish as if it had, when I finish my coffee (or when I forget to finish my coffee, and let it sit around long enough to go cold). Because someone has finally applied the magic of heat-sensitive paint to the magic of Tetris licensing.
Just don't put it in the dishwasher. That'll give you a permanent game over.