Internet celebrity cat, Tardar Sauce, best known as "Grumpy Cat," passed away on Tuesday at the age of seven due to complications from a urinary tract infection. The distinctive looking cat became an iconic model for internet memes due to its perpetually grim-looking facial expressions. It soon led to a mini-empire of licensed products featuring the cat, including a comic book and even a TV movie!RELATED: Aubrey Plaza to Voice Grumpy Cat in Lifetime Christmas MovieTardar Sauce was one of four kittens born to a calico mother and a tabby father. While both of her parents were typical domestic short hairs, Tardar Sauce and her brother, Pokey, were born with a form of dwarfism that gave them flat faces, big eyes and short tails and legs. In addition, Tardar Sauce had an underbite. The combination of the dwarfism and the underbite gave the cat a distinctively dour expression. When Bryan Bundesen, brother of Tardar Sauce's owner, Tabitha Bundeson, posted a photo of Tardar Sauce on Reddit when the cat was only five months old, the cat became an instant sensation. Countless memes were created featuring the cat, which by now had become known as "Grumpy Cat."Bundeson took a leave of absence from her job and she and her brother began to license "Grumpy Cat" for a number of products, with T-Shirts being their most popular item at first. Interestingly, one of the most successful early "Grumpy Cat" shirts was based on a joke from a Kate Beaton Hark, a Vagrant! webcomic.RELATED: When Stan Lee met Grumpy Cat, there was much frowningPopular "meme manger" Ben Lashes began representing Tardar Sauce and the cat has been licensed into comic books by Dynamite Entertainment...and even a Christmas movie for Lifetime with Aubrey Plaza as the voice of "Grumpy Cat"...As part of a promotional deal with the cat food brand, Friskies, Grumpy Cat even began to make convention appearances (she even famously got into a "frown-off" with Marvel icon, Stan Lee, at one of the cons). Multiple Grumpy Cat books have been national bestsellers, including The Grumpy Guide to Life: Observations by Grumpy Cat. The official Grumpy Cat Twitter account (which has over a million followers) announced the death early Friday morning: