The adorable and quirky internet-famous Shih Tzu known as Marnie the Dog crossed over the rainbow bridge this week.
Her owner, Shirley Braha, made the announcement on Marnie's popular Instagram account Saturday.
She wrote Marnie had passed away "painlessly & peacefully" at home at the age of 18.
"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," Braha wrote.
She added she was so thankful for the time she had with Marnie.
"All I can feel right now is loss but beneath that I have so much gratitude. I’m grateful to the universe for entrusting me with her beautiful soul and providing me with the perfect best friend and companion," Braha wrote on Instagram. "Im grateful I was able to give this magical creature the fun and deeply loving life she wanted and deserved."
Braha adopted the Shih Tzu in 2012, she told TODAY in a previous interview, when the dog was somewhere around the age of 11.
Marnie was known for her unique look — she had survived vestibular syndrome, and the residual effects included a tilted head. She also had a long tongue and charming attitude that easily won people over, both in real life and online.
Braha said she thought Marnie's appearance was so cute that she launched the Instagram page that made her famous.
“I never imagined that she would become as wildly popular as she is now," Braha told TODAY in 2014. "I mean, you’re posting these pictures, and people liked them, but it was no big deal at first. ... But in the last two months, she’s gone from 100,000 to [almost 500,000] followers.”
Once she was internet-famous, Marnie began hanging out with celebrities like Tina Fey, Demi Lovato and James Franco.
As Marnie got older, like all dogs, she slowed down. Last week, Braha said she was preparing for the end.
"I’m beyond grateful Marnie has made it this far, but I also understand that part of being a senior dog adopter and advocate is knowing when to let them go," she said.
In her post Saturday, Braha said she was thankful she was chosen to be the conduit for her dog to "bring joy into the world."
"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," she wrote. "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."
Marnie’s story of transforming from a homeless senior dog with matted fur, decaying teeth and a shelter nickname of "Stinky" into a true celebrity is chronicled in the bestselling nonfiction book “My Old Dog: Rescued Pets with Remarkable Second Acts.” Marnie also is the star of her own photo book, "Marnie the Dog: I'm a Book."
As news of Marnie's death spread, other famed Instagram pets and fans posted their condolences in the comments.
"So sorry to read this sad news. She was so lucky to have made it to that age," @wat.ki wrote. "She had a wonderful life. She will be missed. RIP sweet girl."
Perhaps one of the most poignant messages on Marnie's post came from the recently deceased cat Lil Bub.
"I love you Marnie," Lil Bub's commemorative Instagram account posted. "Excited to spend time w u exploring space. Let's go!"