The runners who encountered the beautiful golden retriever offered tributes on social media.
golden retriever sits next to two humans in front of his painted portrait
Credit: David L. Ryan / The Boston Globe via Getty Images

Spencer, the treasured golden retriever who cheered on thousands of Boston Marathon runners with his "Boston Strong" flag, died this month at 13 after fighting several rounds of cancer. 

Holding flags in his mouth, Spencer was a fixture on the marathon route beginning in 2015. He was named the Official Dog of the 126th Boston Marathon last year, and the Marathon announced this week that he would retain that title forever

Spencer, who also worked as a therapy dog, was "an angel on Earth," his owner, photographer Richard Powers, wrote on Instagram. He overcame cancer (and a 3.5-pound tumor) in 2020—in enough time to inspirationally attend the 2021 marathon. 

Unfortunately, he was diagnosed with "inoperable" liver cancer in September, and he died Feb. 17. He was with his family. 

Powers told Good Morning America that his dog's popularity really took off in 2018 when he attended the cold, wet race in a rain jacket. It delighted the runners that year, and many athletes offered touching tributes to Spencer on Powers's Instagram post.  

"I met Spencer while I was running the 2022 Boston Marathon," user heidi_lynn wrote. "I petted him and whispered in his ear—I'm a cancer survivor too. It truly felt like a magical moment and was the highlight of my race." 

I've never done anything as physically demanding as running a marathon, but I can imagine how happy I'd be to see a beautiful golden retriever rooting me on. 

"Like many others, I loved seeing Spencer on the course!" user wwultrakim wrote. "The perfect cheerleader just when we needed it!"

"I feel so lucky Spencer was a part of one of the best days of my life," mutiger1016 wrote. "He was a treasure to all of us. Thank you for sharing him with this entire community!"

Back in January, Spencer attended the unveiling of his portrait, a stunning depiction of him holding his flags in the blowing wind. The painting, by Tom Mosser, hangs in the Powers's home. 

"The sight of Spencer's ears blowing in the wind as he held the marathon banners so firmly on that cold and rainy day is so iconic," Mosser said in a statement. "I've run five marathons so I especially loved seeing the smiles of the runners each year as they saw him. It was such a pleasure creating the piece to celebrate Spencer and the Boston Marathon."