Marnie The Dog, a beloved senior Shih Tzu, died this week, according to an Instagram post on Saturday from her owner.

"It is with much grief I share the news that Marnie passed away painlessly & peacefully in my home on Thursday afternoon at the age of 18," the post read, presumably penned by her owner Shirley Braha. "Her comfort had been notably declining over the past few days with little hope for improvement and she let me know she had had enough."

Marnie earned viral fame by being absolutely adorable. With her drooping tongue, cocked head, and expressive eyes, Marnie racked up nearly 2 million fans on Instagram. She met countless celebs and even had a book.

We here at Mashable were among her fans and were lucky enough to have her visit our office. We dressed her up as some of your favorite characters and, well, just take a look at the lovely results.

Marnie as Patrick. Image: Mashable

Marnie with a pal. Image: Mashable

Just look at that face. Image: Mashable

"I’m thankful I was chosen to be the conduit for Marnie to bring joy into the world," the Instagram post from Braha read. "And I’m thankful for all the human and dog friends Marnie and I made along the way, and the strangers on the streets and on the internet, who have shown us so much love."

"Most of all, I’m amazed that the sweet little hot mess of a pup that I picked up from a shelter at age 11, who at first didn’t seem like she would be around very long at all, has managed to inspire others to adopt senior dogs," the Instagram post read. "When I hear from people that Marnie has made them adopt their senior dogs it’s truly the most beautiful legacy she and I could hope to leave in this world."