An Australian man said he used two cases of beer as a bartering tool to rescue a unique "unicorn" sheep from the slaughter.

Michael Foster, a veteran stock agent, said he was checking out a flock of sheep when he came across Joey, a sheep with one of its horns directly in the middle of his head.

"I thought it might have been a joke to start with, but I thought, 'yeah it looks like a unicorn,'" Foster told 7News Adelaide.

"I've been a stock agent for about six years and it is definitely the first time I have come across anything like it," Foster said. "To the best of our knowledge, it is the only one in Australia."

Foster said Joey was destined for the slaughter, but he was able to save the animal's life by trading two cases of beer for the sheep.

"He runs with the other sheep, it's just funny seeing his horn poking out," Foster said.

Foster said Joey seems made for stardom.

"We'll break him in, take him to shows and pageants, and who knows where we can go, maybe Hollywood," Foster said. "I'm sure the kids will get a big kick out of patting a real-life unicorn, we might even do unicorn rides."

A "unicorn" led California police on a three-hour chase in the Madera Ranchos area in early 2016. The "unicorn" in that case turned out to be a pony that had been dressed up for a photo shoot before escaping.