If you're a Star Trek fan, you already know all about the trouble with tribbles. So why not add this cool 4-inch tall, 15-ounce ceramic Star Trek Tribble Heat Change Mug to your desk to enlighten the rest of the world? In black, it features the words "The Trouble with Tribbles" and Captain Kirk holding a few of the little critters, but when you add a heated liquid the tribbles really start to appear! Do not microwave. Hand wash only. Not dishwasher safe. Ages 13 and up.