This is the $13 Game Boy 16oz Heat Change Molded Mug available from ThinkGeek. When you pour something hot in it (coffee, tea, fresh blood for a ritual) the screen turns from black to Mario rescuing Princess Daisy in Super Mario Land. Unfortunately, like most color-changing coffee mugs it's not microwave or dishwasher safe. But is that going to stop me from trying and ruining it anyways? No it is not. Have you seen my sexy lady coffee mug? She used to wear a bikini when the mug was cold, now she's just topless all the time. "Stay classy, GW." I can't not be, it's who I am.
Thanks to Dave L, who only drinks out of his drinking horn because he's a modern viking. Break down my door with an axe and steal my sundries!