Clearly, he is a hero.

“Good boy, Storm!” a man’s voice says in the video, calling to a golden retriever paddling toward a brown lump bobbing in the water of Port Jefferson Harbor off Long Island. Taking it in his mouth, the dog hauls it toward the beach, a moment filmed by his owner on Sunday that has been seen by 5.2 million and counting on Facebook.

The lump was a fawn, which the dog dragged onto the sand. There it lay, alive but barely moving.

Storm gently nudged the fawn’s belly. It scarcely responded. He nuzzled it again. Nothing. He pawed at its tiny hooves. Then the video ended.

The video footage has launched Storm to sudden social media stardom and sent him on a tour of morning TV talk shows.

Banish any thought that the dog, a 6-year-old English golden retriever owned by Mark Freeley, a personal injury lawyer from East Setauket, N.Y., might have simply been following his instinct to retrieve.