A San Francisco Bay Area man who lost his beloved pooch to cancer is keeping his fallen friend's memory alive by sending tennis balls to dog lovers around the country — and even the world.

Chris Stonag-Ratti launched the initiative on Instagram last month, with a post promising to send anyone a free tennis ball if they'd use it to play with their dog like Sontag-Ratti wished he could play with his.

His Boxer-Rottweiler mix, "Everything," succumbed to cancer in January 2014 at the age of 12, and pain of her absence is still very real. Her name — chosen at random when Sontag-Ratti adopted her in 2002 — turned out to be as perfect as it was unusual.

"Everything" became just that to Sontag-Ratti.

"Some people have religion and some people have, you know, their materialistic things, but for me it was the dog," Sontag-Ratti said.

During tough times and while tempted down dark roads, his dog was one thing that kept him from heading too far astray.

"Any time I got into troubled water, she was like an extra reason for me to make sure to get out and stay out," Sontag-Ratti said. "No matter what, I had her as like this responsibility and I never let that go.

Sontag-Ratti was devastated to lose her. But if time won't heal the wound, perhaps kindness might ease the pain.

He embarked on his mission with 100 tennis balls and low expectations.

WATCH MORE BAY AREA PROUD STORIES

"I figured I was gonna be sitting in my room with about 80 or 90 tennis balls but it didn't happen like that," Sontag-Ratti said.

His Instagram post garnered more than 8,000 likes in a single day, and his tennis ball supply was exhausted practically overnight. Sontag-Ratti now has a waiting list hundreds of dogs long.

People from around the country and the world have been sending in requests, along with notes of thanks and encouragement. Many recipients then send pictures of their dogs playing with the tennis balls.

"I feel great about it. It wasn't just about Everything and myself. It was about affecting other people and like getting them in contact with their, with their pets," Sontag-Ratti said. "So that maybe a backyard dog on a chain, hopefully, they'll let the dog off the chain and throw the ball or something."

It's a lesson worth learning. If you ever feel like you've lost everything, throw a little love into the world, and watch it fetched right back to you.