It's the Trump conundrum that has the experts stumped.
Not his seemingly unstoppable popularity or how he's planning on actually getting Mexico to pay for that wall.
But how he has managed to have such a, well, unique hairdo.
That glorious ski slope of a golden mane. At times it seems so thin and fragile that it's barely there at all. Then a gust comes his way and his locks take flight giving him the look of man who has just been electrocuted.
It's been compared to an ear of corn, a troll and even a cresting wave.
Yet the candidate has always insisted his hair is indeed his hair.
But the author of a new book on Trump says the Presidential wannabe's noggin is the result of an experimental, and now widely discredited, treatment for hair loss.
And unlike Trump's standing in the polls, Michael D'Antonio said on Thursday "I don't think it worked very well."
There have been a number of explanations for the billionaire's bob, from a simple comb over to follicle surgery. However D'Antonio, whose has just published a book on Trump called Never Enough: Donald Trump and the Pursuit of Success, the answer is a '90s fad that never caught on. For good reason.
On Sydney's 2UE Breakfast Show with John Stanley and Garry Linnell on Thursday morning, amid discussions of the Republican candidate's "narcissistic" yet "brilliant" personality and his belief his is "genetically superior" to the people he wishes to represent, D'Antonio also let rip on Trump's tufts.
Asked about the reasons behind his curious style, the author said he expected it was a result of an invasive operation called "flap surgery".
"There was, for a brief period in the early '90s, there was a surgery that was done where they would cut a way the hairless part on top of a man's head and stitch it together," D'Antonio said.
"It would change the look of a balding man's head and I think he has that surgery and I don't think it worked well".
The procedure involves finding a piece of the scalp with hair on and then cutting it on three sides to create said flap. This slither of skin is then twisted, pulled and forced into a new position it to the hairline where the faulty follicles are.
As it's never fully severed from the head, the patch should retain its blood flow and stay alive. Should being the key word.
There were telltale signs of the surgery, D'Antonio told Linnell and Stanley.
"It is his hair, it's strangely coloured [but] it's in the wrong spot.
"He has a hair line in the front that was created by the surgery and I suspect there's a big patch in the middle and then it's all combed over every which way to form this structure."
The procedure is not recommended by the American Hair Loss Association who say on their website, even in the best cases, the surgery will leave an "unsightly knot" where the flap has been twisted.
As the new hairline is from a different part of the scalp, the hair will inevitably grow in the wrong direction adding to the odd overall appearance while a scar occurs in the area where the skin was taken from.
But that's not all. Loosened skin in the forehead can over hang the brow "giving a Frankenstein or Neanderthal appearance" and necrosis of the flap can set in leaving a "horrific scar".
The organisation doesn't mince its words. "If your hair restoration surgeon offers this procedure for common hair loss, leave immediately."
"I want to use hair spray"
Trump's mane, or lack of, has been a talking point for some time. US TV and film hairstylist, Amy Lasch, who worked on the set for the first two seasons of The Apprentice, said Trump refused to let her touch his famous do.
"If I noticed a flyaway that the camera was sure to pick up, I would hold a large mirror up to Donald and ask, 'Do you want me to fix it?' I knew damn well - ask before I raised a finger to that hair," she told the New York Post.
"I think it's all his hair - through transplants," says Louis Licari, who coloured the hair of Trump's first wife, Ivana, for 20 years.
"I saw him several times in the office of Dr Norman Orentreich in the early '80s," Licari adds, referring to the specialist who, in 1952, performed the first-ever hair transplant.
As for how Trump gets that soft-serve swirl? Aerosol hair spray, which environmentalists are trying to eradicate. The candidate griped at a South Carolina rally earlier this year about claims that "hair spray is going to affect the ozone. They want me to use the pump [spray]. And then it comes out in big blobs ... I want to use hair spray!"
In December, Manhattan hairstylist Caroline Mitgang told website Quartz that rumours of a wig were probably wide of the mark.
"I'm sorry to sneeze on everyone's cake, but my professional assessment is that Donald Trump just has a dated hairstyle nobody likes."