Is it a sheep ... or a goat? Or a sign?
4 April 2014 Last updated at 03:58 ET
Geep: Rare 'goat-sheep' born on Irish farm
The unexpected arrival is thought to be the result of mating between a goat and one of the sheep farmer's Cheviot ewes.
Mr Murphy said the cross-breeding was not intentional. He described it as a "pure shock to the system" and said it would be a "one-off" event on his farm.
"I've never seem anything like him before," he told the Irish Farmers Journal, adding that his family had been involved in sheep farming for "generations".
Mr Murphy confirmed that the geep appeared to be healthy and "thriving" and was able to run faster than other lambs that were born around the same time.
"He's unbelievable," he said. "He's so fast you'd have to get him into the pen to catch him. There's no chance you would catch him otherwise."
The sheep farmer, who also owns Murphy's pub in Ballymore Eustace, County Kildare, spoke to the journal in a interview headlined: Ewe gotta be kidding.
He said he witnessed a goat mating with ewes on his farm during "tupping" season five months ago, but had given the matter little thought until the geep appeared,
He said the new arrival had created a lot of laughter in the pub, when he showed mobile phone pictures of the hybrid to his customers and friends.
"He's an unusual character," Mr Murphy added, saying the animal was developing a set of horns on its head.
The Irish Farmers Journal said it was the first time it had reported the birth of a healthy geep in Ireland.
A spokeswoman for Ulster Farmers Union the said the live birth of a so-called geep is a very rare event and they are not aware of any currently in existence in Northern Ireland.
She said this form of cross-breeding, on the rare occasion it does occur, is likely to involve a buck goat and a ewe.
However, the geep usually dies during the ewe's pregnancy or is stillborn.
Mr Murphy said the ewe in question was raising the geep "just like a lamb".
As for the hybrid animal's future, the farmer said he was not planning to send the geep for slaughter but would try to keep it for as long as it was practically possible to look after it.
But he has not yet chosen a name for his new pet.
"We've no name set up yet, no. We might look for one" Mr Murphy said.