A cat that naturally looks grumpy. His full name is Tartar sauce, but his fame on the internet site reddit.com sparked the nick name grumpy cat. A subsequent video on youtube garnered several million views, which cemented grumpy cat's place as the most widely loved feline.
The grumpy look on his face is likely due to inbreeding, but his brother pokey does not share the same facial expression.
Grumpy cat has appeared on several television newscasts, has an entire subreddit to his name (/tard) and even clothing which features his face.
Person one: hey man have you seen that picture of the cat that looks upset?
Person two: HIS NAME IS GRUMPY CAT! Get it tight or get out