When Dustin Britton ventured 100 feet from his Wyoming campsite last week, he was prepared to cut wood, not go saw to paw combat with a starving mountain lion.
"Within seconds, I see this lion over 20 feet from me just standing there looking at me. I could see just its head there in the grass, of course it scared the pants off of me," Britton told ABC's "Good Morning America Weekend."
Britton was afraid, but he said it didn't appear that the lion had any fear at all. Standing just 100 feet from his wife, Kirsta, and two toddlers at the campsite, Britton tried to run away from the lion into a clearing, but the lion followed him. Lucky for Britton, he had a chainsaw.
But undeterred by Britton's revved up chainsaw, the lion pounced.
"It slowly came out of the brush and out into the open, and it just charged right at me and lunged at me," said Britton.
It literally was man against beast.
"It pushed me back a few steps," said Britton, who used his training in the Marines to fend off the animal. "As it came up, I brought the saw up and so it batted my arms and the saw three or four times. Then I hit it as hard as I could with that saw at full throttle trying to hit it in the neck."
The lion backed down, but Britton said it "didn't leave in a hurry."
Back at the campsite, Britton collected his family and stayed in the RV for the night. The 32-year-old mechanic and ex-Marine from Windsor, Colo., found a ranger at the Shoshone National Forest and informed him of the attack.
Britton's chainsaw attack inflicted a six- to eight-inch gash on the lion's shoulder, but it wasn't enough to stop the animal.
"You would think if you hit an animal with a chainsaw it would dig right in," Britton told The Associated Press. "I might as well have hit it with a hockey stick."
The mountain lion was later killed by wildlife officials after it attacked a dog brought in to track the animal. Officials say the lion appeared to be starving and was 4- to 5-years-old.
"Of course it seemed plenty big to me, but I guess I was told it weighed 100 pounds," said Britton. Most healthy adult male mountain lions weigh about 150 pounds.
Wildlife officials said Sunday evening's attack about 27 miles west of Cody was highly unusual because mountain lions are reclusive by nature. Only eight cases of mountain lions acting aggressively toward humans have been documented in Wyoming over the last decade.
Initial tests conducted on the lion for rabies and other diseases came up negative. Its carcass was taken to the Wyoming State Veterinary Laboratory in Laramie for further testing.
"It was acting completely out of character for how a lion would normally act around a full-grown man who has a chainsaw in his hand," said Wyoming Fish and Game biologist Mark Bruscino told the AP.
"I couldn't believe that it wasn't afraid of me or the saw," Britton told "Good Morning America Weekend."
Britton got away with just a small puncture wound on his arm, and the family continued their vacation in Wyoming and Montana.
The Associated Press contributed to this report.