When visiting national parks, one expects to leave with fond memories and perhaps a keychain or a t-shirt. For an 83-year-old woman from Greenville, South Carolina, however, a trip to Yellowstone National Park ended up with her bringing home an unplanned—and certainly unwelcomed—souvenir, courtesy of a bison.

The incident occurred on June 1 near the Storm Point Trail at Yellowstone Lake. As she walked, probably marveling at the scenic beauty and maybe contemplating the simplicity of life in retirement, she found herself on the receiving end of a bison's decidedly ungentle reminder to respect personal space.

In an encounter that probably reminded her of a rougher-than-average square dance, the bison lifted her about a foot off the ground with its horns. Suddenly, she was airborne, experiencing a sensation not unlike that offered by the up-and-down ride of a mechanical bull but without the safety of an inflatable landing zone.

Emergency responders quickly arrived, transporting her to the Lake Medical Clinic. From there, she was treated and flown to Eastern Idaho Regional Medical Center in Idaho Falls, Idaho. It's not every day you get to see multiple states from a bison's horn to a hospital bed in a matter of hours.

Park officials noted that the bison was 'defending its space'. In fairness to the bison, personal space is somewhat hard to measure in the great outdoors, especially when the only units of measurement available are "quite far" and "here there be horns."

The woman sustained serious injuries, but officials have not provided any updates on her condition. This incident is under investigation, presumably seeking to answer pressing questions like, "What is the bison planning next?" and "Did it act alone or were there other herbivorous conspirators?"

Bison have injured more people in Yellowstone than any other animal, proving that they are less teddy bear and more top-of-the-food-chain non-carnivorous juggernauts.

As a reminder to less seasoned adventurers and thrill-seekers, park authorities gently suggest maintaining a respectful distance from these wildlife residents. They recommend staying at least 25 yards away from bison, which, in case you’re lazy at math like yours truly, is about the length of a regulation swimming pool. That's a small price to pay to avoid ending up on a gory—pun intended—highlight reel.

While bison are not normally aggressive, they will defend their space when threatened. This particular bison was clearly in a self-defense kind of mood, perhaps having had one too many instances of invasive paparazzi-like tourists coming too close for comfort.

The moral of this encounter is as old as time: Nature has a funny way of reminding us that it, too, needs its bubble. So next time you’re at Yellowstone, feel free to enjoy the epic landscapes and awestriking wildlife. Just don’t forget that some of these majestic creatures have no qualms about escalating a 'Get Off My Lawn' encounter into a full-blown 'Here's a Trip to the Emergency Room' extravaganza.