Colonel Meow's human made the tragic announcement on Thursday.
"Colonel Meow passed away yesterday evening," Ann Avery wrote in a post to his popular Facebook page. "I will post more about the details when I've had a few days to grieve. Thank you so much for your understanding, Minions. Your love and support has meant the world to us both."
Avery and Eric Rosario adopted the colonel in Seattle and brought him to Los Angeles, where his penetrative stare and mass of unruly fur earned him thousands of social media followers on Facebook, Instagram and YouTube.
"He has already survived a 50/50 chance surgery, a blood transfusion that they THOUGHT would send him into heart failure and now we need YOU to get him out of the woods," his owner wrote at the time.
Lil Bub, another celebrity cat and one of the Colonel's close friends, wished him a safe recovery.
"May his enemies in the afterlife quake with fear, for he comes once again to defeat them. Tyranny cometh, and his name is Colonel Meow," wrote one commenter. "I'm very sorry for your loss, he was a wonderful creature who brought a lot of happiness to a LOT of people."
"With the number of worshipers he has on Earth, he will reign as a god in the afterlife, pushing Zeus off of his throne and making Vulcan warm his chair," wrote another.