Balltze, the pooch who shot to viral fame as meme dog Cheems, died during a lung operation on Friday, prompting an outpouring of grief from online fans.

The 12-year-old shiba inu was best known for the “swole doge versus cheems” meme, a popular meme template that juxtaposes an alarmingly muscular doge – another dog meme based on a shiba inu named Kabuso – against a deflated-looking Cheems.

“Ball ball” – as Balltze was also affectionately known to fans – died on Friday morning during thoracentesis surgery, said his owners in an Instagram post on Saturday. Thoracentesis is a procedure that drains fluid from the lungs.

Balltze, who lived in Hong Kong, had been battling leukaemia, a journey that his owners documented on his Instagram account, which had more than 800,000 followers.

“Originally, we wanted to arrange chemotherapy or other possible treatment for him after this operation, but it is too late now,” said his owners in Saturday’s post.

“Don’t be sad, please remember the joy that Balltze brought to the world. A shiba inu with a round smiling face connecting you and me,” they added.

“He has helped many people during the pandemic and brought a lot of joy to many of you, but now his mission has completed.”

Balltze’s death has sparked an outpouring of grief, with Saturday’s post announcing his death attracting more than 33,000 comments from fans.

“You will live on forever through memes,” said Instagram user cheemsd.

Donations and proceeds from the sale of Balltze merchandise during earlier fund-raising efforts for treating his illness will be given to local animal charities, said his owners.

They added: “Thank you everyone, thank you, Balltze knows how much he was loved by all of you.”