Sure a ninja mug is cool, but if you get one you're never going to be able to find it. Even if it's just sitting there, in the middle of your desk, right in front of your face. Ninja mugs are seen only when they want to be seen, and ninja mugs are heard only when...picked up and dropped on their ass by some co-worker's damn kid. Why aren't you in school, you clumsy bundle of thumbs?! ... Well if it's a snow day, why aren't you at home shoveling snow?!
ThinkGeek's ninja mug comes with all necessary stealth-dealing, hot-beverage-drinking attire, including a removable black jacket (zarf), samurai sword (stirrer), and shuriken (coaster).
Muchas danke to Like Cool.