A picture showing a woodpecker flying through the air in England with a weasel clinging to its back is the subject of debate and parody online.
Wildlife experts have given their support to the photograph.
The image of the wide-eyed bird and its stowaway was apparently taken by photographer Martin Le-May at a nature reserve in Essex.
Mr Le-May was walking at the Hornchurch Country Park with his wife, Ann, in the hope of showing her a green woodpecker.
After hearing "distressed squawking" he says he spotted the bird with the small mammal on its back, and took a series of photographs as the startled pair flew past.
One photograph has become a viral hit on social media, triggering a variety of creative memes with characters such as Russian president Vladimir Putin, the wizard Gandalf and even Disney character Buzz Lightyear, all apparently riding with the bird.
John Travolta is all over the weasel and the woodpecker pic.twitter.com/HMxoDInWbh— Elliot Wagland (@elliotwagland) March 3, 2015
What do you see? Weasel and woodpecker or white and gold? pic.twitter.com/aHZrWnH24D— The Poke (@ThePoke) March 3, 2015
Mr Le-May is adamant that his photograph is real.
He told ITV News that he saw the woodpecker "unnaturally hopping about like it was treading on a hot surface", and that when it flew past him "it was obvious it had a small mammal on its back and this was a struggle for life".
After it landed near him and his wife he believes the weasel became distracted and the woodpecker seized its opportunity, "gathered its self respect and flew up into the trees and away from our sight".
@ DanGraur I have the blurred photos of the rest of the event which was witnessed by another person. Thank you— Martin Le-May (@KingYamel) March 2, 2015
He added: "The woodpecker left with its life, the weasel just disappeared into the long grass, hungry."
Wildlife presenter Steve Backshall says he thinks the picture is genuine. He told the BBC's Newsbeat: "For the bird to be able to fly is pretty extraordinary, but not unheard of, so I have no reason to doubt it."
Mr Backshall suggested the weasel was probably trying to attack the bird, adding: "The weasel is pretty fascinating. It can kill things much bigger than itself, so it's an impressive little creature in itself when you think about its size."
And Mick Greenslade, a park ranger at Hornchurch Country Park, says he has no doubt the photograph is real.
He said: "I am just mind-blown by it. We always see weasels in the park while they are hunting, but for somebody to be able to get a photograph, it is just nature at its best.
"I have no reason to doubt it - he was just in the right place at the right time, and it was a once-in-a-lifetime photo."
Mr Greenslade said the weasel in question was likely to be a full-grown adult.
Weasels are mammals, and only live for two or three years.
"It is probably about six inches long," he said. "People mistake a weasel for a stoat, which are bigger and have a black tip on the end of their tail.
"It only weighs about the weight of a Mars bar. It is not a big, hefty animal but it is very feisty and will attack mice, voles, shrews, a bird if it is close enough and even a rabbit. It is very much an opportunist."
The ranger believes the weasel was probably attracted by the woodpecker's vivid colour or smell and decided to attack, going for the throat and then jumping on to the bird's back for the kill.
"The bird's first instinct is flight," he said. "In the meantime the weasel has clung on for dear life and off they have flown. It is probably the first time the weasel has flown, and no doubt its last. It is just the unpredictability of nature."
Mr Le-May defended his photograph, saying to one doubter on Twitter: "I have the blurred photos of the rest of the event which was witnessed by another person. Thank you."
But others questioned the veracity of the image. Evolutionary biologist Dan Graur said: "This is a fake photo if I ever saw one. The uniform blurred background is pure photoshop," adding: "There are tons of pictures of woodpeckers at flight. This one is a taxidermied one."