She was the little kitty with a huge scowl. Grumpy Cat, whose real name was Tardar Sauce, catapulted to fame six years ago after her owner posted a photo of her on Reddit. She quickly became the perfect way to express frustration with an imperfect world through thousands of memes. Her owner, Tabatha Bundesen, said Grumpy Cat died of complications from a urinary tract infection on May 14. But the sourpuss' legacy lives on, off and online.