Grumpy Cat initially met fame on the link-sharing website Reddit in 2012, and quickly went viral. The original uploaded image garnered one million hits in its first two days on photo-hosting site Imgur. Known for her grumpy frown, the cat's photo is usually accompanied by captions that are equally sour. Her popularity led to T-shirts, calendars, gift wrap and a best-selling book available in 14 languages and even an agent. The cat's unusual appearance was not in fact due to her temperament but an unusual combination of an underbite and feline dwarfism, a form of genetic mutation. Grumpy was in fact very pleasant and playful.