A herd of "possessed" cows attacked and injured a man in South Auckland's Totara Park on Sunday afternoon, ripping hunks of flesh from his body.
The man suffered injuries to his leg after he helped a woman who was by herself and being attacked by the cows first.
Witness Mike Small told the Herald the man saved the woman before the animals turned on him.
"He had a laceration about the size of a palm out of the back of his hamstring, just ripped off ... and another couple of tennis ball sized chunks out of his shin.
"There's no nice way to put it: He got f....d up," Small said.
Small and his wife were biking through Totara Park about 4pm when they heard a spine-chilling scream.
Small saw the woman on the ground with several cows surrounding and attacking her.
"All of a sudden this guy appeared and helped her to her feet and then the cows knocked him to the ground and trampled him.
"I took over there as fast as I could and by the time I got there he had managed to get himself to the nearest fence line and over the fence to protect himself.
"That's when I saw his injuries. He was pretty smashed up," he said.
The woman who was first attacked by the cows contacted St John to get an ambulance to help the rescuer, but she told the witness they wouldn't come if the agitated cows were still there.
Hiding in a pocket of native bush behind a fence, Small climbed over the fence to see if he could slowly move the cows away to allow the ambulance to get through.
"They started clawing the ground and snorting at me like I was a matador.
"We had to pick up the patient and move him to the other side of the native bush that we were sheltering in to enable ambulance staff to even get in," Small said.
The herd of about a dozen cows had a mother and yearling in the group, all without horns.
Small said the cows were rocking back on their hind-legs and raining down on the victim who tried to free himself from the attack.
The fast-paced attack didn't last long but frightened Small and his wife who frequently use the park.
This morning his wife had run around the track and said to him after the incident that "could have been her".
"I wouldn't be exaggerating if I said it was pretty frightening at times because you didn't know what the stock were going to do. It was insane, it was nuts.
"There were front feet off the ground raining down on him. They were head down and if they had horns they would have been goring him," Small said.
A St John spokeswoman said they attended the incident, receiving a call around 3.50pm. A patient with moderate injuries was then transported to Middlemore Hospital.
Auckland Council have been contacted for comment.