On Twitter, hundreds of accounts use Grumpy Cat’s most famous photo, often with the tagline “I had fun once. It was awful.” The most popular account had 951,701 followers at the time of this writing. Tard’s owners have no idea who runs that account.

People dressed up their children as Grumpy Cat for Halloween. Grumpy Cat memes were passably happy when the world was supposed to end in December, and then alternatively indifferent and mad at the Mayans when it didn’t. Christmas was the high season for bah-humbug memes bemoaning the spirit of the holidays or suggesting creative, and mildly offensive, places to put mistletoe.

South Florida cat lovers have embraced Grumpy Cat and shared photos of their own dissatisfied pets. Neil Albert of Hallandale Beach submitted a photo of his two cats — the playful Smokey (“the one that’s the size of a moose”) and Serena, the sweet little kitty who loves attention.

“I’ve been working with animals long enough to understand that they all have personalities the same as people,” Albert said. “There are those that are bullies, playful and of course, grumpy.”

Albert runs an organization, Cat Pals, that cares for feral cats in Hollywood, practicing “trap, neuter and release” rather than euthanizing them.

Grumpy Cat’s agent, Ben Lashes, said the cat’s owners are donating part of the money they earn on merchandise and licensing — which Bundesen said is going to “No Kill” animal shelters. Lashes said he is allowing Grumpy Cat’s image to be used only for “things that are cool.” Next, he imagines a Grumpy Cat animated series.

“Before I met Grumpy Cat I was like, ‘What if I get there and it’s smiling all the time? It would terrible to see this cat happy,” Lashes said. “The minute I met Grumpy Cat I was like, ‘Oh my gosh, it always looks grumpy and it’s so cute at the same time.’ The cat never makes a happy face…A lot has changed in the Internet cat world, but this is one of the craziest cats I’ve ever seen.”

This report includes comments from the Public Insight Network, an online community of people who have agreed to share their opinions with The Miami Herald. Sign up by going to MiamiHerald.com /Insight.