Cathy Hayes, a teacher from Utah, was catching a bison on video, joking with her husband, Jeff, and his brother, Donald, about getting a shot of Donald being gored by the animal -- when Donald got too close - and it attacked.
The bison, clearly agitated, charged Donald and then Cathy, sending her into a panic. She ran for cover behind a tree, but the bison kept coming.
The car horn honking is clearly audible as Jeff tries to deter the bison. So is his yells of "Back," and screams - with the video rolling all the while.
"I could hear him over me stomping and snorting," Cathy said later, "and I just knew. I knew at that second that was it. You know, I thought, "This is going to be my last moment. It's going to be in Yellowstone Park getting tromped by a buffalo." "
On The Early Show" Friday, Cathy told co-anchor Chris Wragge the bison "flipped me end-over-end like a rag doll, in the air."
It turned out she didn't suffer life-threatening injuries, but was pretty badly banged up. Her knee was the size of a football and she has big brusies ans scrapes on her leg. Donald broke his shoulder when he tripped and fell.
And the incident may not have been the bison's fault.
A second look at Cathy's video shows the animal was apparently provoked. It seems the bison was hit it in the back with a stick -- a vivid reminder of the park's policy to keep your distance from wildlife.