Harrowing moments were captured on camera as a bison charged at visitors in Yellowstone National Park in Montana.
A couple was walking in a large field. Then, the animals charge.
Two women start running away, but one of them trips and falls.
Voices off screen yell "play dead! Play dead!" and that's exactly what she does.
You see her lying motionless as the bison checks her out, and eventually gallops away.
The bystander who recorded the incident says the woman is a local and knew to play dead in that situation.
The woman was not hurt.