VIDEO: Moment furious Yellowstone bison flipped tourist during photo session

A relaxing evening walk turned into a terrifying ordeal after a massive male bison, weighing an estimated 2,000 pounds, charged and seriously injured an elderly tourist at Yellowstone National Park in the US.

In a video seen by TNX Africa, the incident unfolded near the Bridge Bay Campground shortly before sunset.

The footage shows 65-year-old Carl Isom-McDaniel and his young grandson stopping to photograph the bison as it rested in the grass, only for the animal to suddenly leap to its feet and charge at them.

The encounter escalated quickly after the bison became visibly agitated, rolling on the ground before launching its pursuit.

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A nearby pickup truck attempted to intervene, but the driver was forced to speed away after the bison briefly turned its attention to the vehicle.

It then resumed chasing the pair, sprinting through a grove of trees and kicking up a thick cloud of dust.

Despite their efforts to escape, the bison caught up with Isom-McDaniel, goring him with its left horn before tossing him into the air.

He suffered multiple injuries and was rushed to a nearby hospital.

Witnesses told the Cowboy State Daily that he remained conscious and surprisingly upbeat while waiting for help.

"The bison hooked him with his left horn on his hip and tossed him in the air. He made a perfect flip and landed on his side. He was in a lot of pain with his leg, and otherwise he was conscious the whole time, in good spirits, joking," said Mike Macleod, who recorded the incident.

According to the BBC, the National Park Service (NPS) has repeatedly warned that bison injure more visitors in Yellowstone than any other wild animal.

Although they often appear calm, they can run up to three times faster than humans. Park guidelines advise visitors to stay at least 25 yards away.