Portland resident Cassie Hopkins said instinct and adrenaline took over when she watched a mountain lion come out of nowhere and snatch up her dog.

"I was just thinking, I have to get over there, and I have to get this thing off my dog."

Hopkins said she was visiting Montana for the first time with her boyfriend, on a walk with her dog, when she heard a crash behind her.

"I heard just this big thunder behind me and I was turning around thinking, oh, we must have scared a deer, and then I saw this huge mountain lion just flying through the air."

The lion picked up the dog in its mouth and carried it for at least one hundred feet.

Hopkins said she gave chase immediately, throwing rocks and yelling.

Patrick Muri, Hopkins’ boyfriend, said he was inside getting dressed when he heard screaming.

"I bolted down,” said Muri. “In the dusk I see Cassie standing there, and the dog, and this mountain lion just broadside to us."

When confronted by both Hopkins and Muri, Hopkins said the mountain lion dropped her dog.

Incredibly, Hopkins said the dog got away with just some minor puncture wounds.

Hopkins also injured her foot chasing after the mountain lion, and said she didn’t process what had happened until the car ride to the vet and hospital.

"When we were driving into Missoula, I was thinking about proximity and how close it actually was, and that was pretty wild."

Montana Fish, Wildlife and Parks officials were called to the scene, and were able to shoot and kill the mountain lion.

They said the cat is skinny for its size, which they said might explain the aggressive behavior.