A terrifying encounter at Yellowstone National Park has left a tourist seriously injured after a massive bull bison charged at him before launching him several feet into the air.

The shocking incident unfolded at the Bridge Bay Campground on Friday and was captured on camera by photographer Mike MacLeod, who was camping nearby when the drama erupted.

Video of the attack shows the unidentified man walking through the campground with his grandson as the bison, which had moments earlier been rolling in the dirt, suddenly turned aggressive.

The pair attempted to get away by moving behind a group of trees, but the animal pursued them.

The grandson managed to escape, while the older man was chased around the trees before the bison caught up with him.

Witnesses said the bull hooked the man with one of its horns before tossing him roughly eight feet into the air. He landed heavily on the ground and suffered what have been described as significant injuries.

MacLeod, who filmed the attack, said he feared the bison was about to gore the injured man as it stood over him after the attack.

"I had to get the bison's attention," he told Cowboy State Daily, explaining that he stopped filming, ran toward the animal and shouted in an effort to distract it.

Other bystanders joined him, eventually forcing the bison to retreat before emergency responders arrived.

After the danger had passed, witnesses rushed to help the injured tourist.

According to MacLeod, the man complained of severe pain in his hip and leg, although those assisting him could not immediately see any external injuries.

His grandson later said his grandfather had suffered serious injuries and remained "not out of the woods."

The reason for the attack is not yet known, but MacLeod believes the bull's behavior was linked to Yellowstone's annual bison rut, which takes place between June and September.

During that period, male bison become significantly more aggressive as they compete for mates.

The photographer said the animal had already charged at a group of children earlier in the evening and appeared to be "charging anything and everything" before the attack on the tourist.

Perhaps most surprising, witnesses said the victim and his grandson had been keeping what appeared to be a respectful distance from the animal.

MacLeod said the pair were simply out for an evening walk and happened to cross paths with an unusually agitated bull.

The National Park Service has not yet released details about the incident or provided an update on the tourist's condition.

The attack marks the second reported bison-related injury in Yellowstone this year.

Just weeks earlier, a 12-year-old visitor was injured near the park's Mud Volcano area, prompting renewed warnings from park officials about keeping a safe distance from wildlife.

Bison are responsible for more injuries to visitors in Yellowstone than any other large animal, and despite their calm appearance, they can run several times faster than humans and become unpredictable when they feel threatened.

Part of the fun of going to wildlife reserves is not just seeing nature in all its glory, but having the chance to encounter animals in their natural habitat - free (mostly) of human interference or the confined spaces of zoos. That way you can get to see some of the fine flora and fauna of this Earth, without feeling bad about negatively affecting their lives in any way.

However, there are some people out there who push the boundaries. National parks tend to have rules in place, but they're hard to enforce if a random tourist wants to get as close as possible to the action. For instance, in Yellowstone National Park, there are clear guidelines on how near you are allowed to get to certain creatures, but not everyone follows their advice.

Just last year, there were two incidents of bisons attacking visitors to the park. In May, one woman was walking around the bend of a trail when she was hit by a bison she hadn't seen, getting away with minor injuries. The following month, another woman was gored by a bull bison when she got within ten yards of it - while the suggested safe distance is considered to be around 25 yards, or 7t feet, for this particular animal.

"Animals in Yellowstone are wild and unpredictable, no matter how calm they appear to be," the park's guidelines state. "Give animals space when they're near trails, boardwalks, parking lots, or in developed areas. If you can't maintain these distances, turn around and find an alternate route."

Well, not everyone is so keen to follow these rules. In fact, in this case, the problem was less that someone got close to a bison, but that they actively taunted the aggravated animal. One man got up close to stare down a bison in the middle of a road, surrounded by traffic. The creature was mostly disinterested, but was quickly angered once the man pounded his chest and approached it.

Lindsey Jones was driving through the park with her family when she saw the cars slow to a stop on this road, as a bison wandered through the area. When she saw the man get out of his car to taunt the bison, she used her phone to film the ridiculous act. Jones posted the clip on Facebook, where it has since been viewed more than a million times.

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The bison charges him, but this isn't enough to get the man to back down, as he gets back to taunting the bison once more. As it began its second charge, you can hear Jones exclaim, "Oh god, I can't watch anymore!"

Another person in the car can be heard shouting at the man to "Get out of there!" Eventually the bison, luckily for the man, loses interest and turns away from him. If things had ended up any differently, he only would've had himself to blame.

A nine-year-old girl has been taken to hospital after a bison charged at her in Yellowstone National Park.

The girl, who has remained unidentified, was tossed violently into the air after the animal ran at her during a visit to the park in Wyoming, USA.

The National Park Service confirmed the incident in a statement released yesterday.

Watch the shocking footage below - the poor girl went flying: 

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The girl was reportedly with a group of people in the Old Faithful Geyser area of the park, and was standing within five to ten feet of the bison when it charged.

The group was comprised of 50-60 people, who were gathered near the animal for around 20 minutes, before doing something that "[caused] the bison to charge". The park service did not specify what provoked the animal.

Eighteen-year-old Hailey Dayton, who caught the event on camera, says she was filming the bison eating when it suddenly attacked the young girl.

"My brother and I were looking at the hot springs, and we saw a bunch of people running down the path to the bridge. We saw through the trees some people petting the bison, super close," she told NBC News on Wednesday.

"Because it was agitated by all the people and noise, it just kind of attacked," continued Dayton, who was visiting the park on a family road trip. "After that, everyone was screaming. There were a bunch of kids crying."

While the park service's statement confirmed that the 9-year-old was "assessed and treated by park emergency medical providers, and later taken to and released from the Old Faithful Clinic," they did not detail her injuries.

The incident is still under investigation, and no citations have been served.

The National Park Service reiterated that animals at Yellowstone National Park are wild, and that visitors should always stay at least 25 yards away from bison, deer, moose, and elk.

A reporter has taken to Twitter to share the hysterical moment a herd of wild bison headed towards him, prompting him to run for the hills.

Deion Broxton, a reporter for NBC Montana, explained in the tweet that the herd was walking "right toward him" while he was working in Yellowstone National Park.

This is the moment Broxton runs away from broadcast after spotting a herd of wild bison heading his way:

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While the herd is not seen in the video, Broxton is clearly spooked by something as he utters the words, "Oh my god, oh my god. Oh no, I 'ain’t messing with you," before quickly dashing away from the animals.

The clip has since garnered an impressive 64.5k retweets and 322.3k likes.

In a later tweet, the reporter shared a video of the animals, which he filmed once he was far enough away from them.

"Here's the video of the bison I shot once I got a safe distance away lol [sic]," he wrote.

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The official Twitter account for Yellowstone National Park was tagged in the original tweet, prompting this reply: "A perfect example of what to do when approached by wildlife! Rolling on the floor laughing Thanks Deion for putting the #YellowstonePledge into action! [sic]"

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Yellowstone National Park recently announced that it is currently closed to all visitors until further notice.

A statement on its website reads:

"Yellowstone and Grand Teton national parks are announcing modifications to operations at the request of local county health officers from Park County, WY, Park County, MT, Teton County, WY, and Gallatin County, MT. The health and safety of our visitors, employees, volunteers, and partners is our number one priority.

The National Park Service (NPS) is working service-wide with federal, state, and local authorities to closely monitor the COVID-19 pandemic. Effective immediately, Yellowstone and Grand Teton national parks are closed to all park visitors until further notice. There will be no visitor access permitted to either park."