Paul Karason, a man known for his blue skin, passed away Monday. Reports indicate that he died of a heart attack and stroke in a Washington hospital.
The "blue man" known as "Papa Smurf" was born a fair-skinned, freckled boy with reddish blond hair. But later, he developed skin with a bluish tinge.
This was the result of a rare medical syndrome known as argyria or silver poisoning from dietary supplements, which he says he took years ago.
In a 2008 interview, he said the blue tinge started more than a decade earlier when he saw an ad promising health and rejuvenation through colloidal silver.
He drank about 10 ounces a day of the substance, dissolved in water.
Karason said he hadn't even realized his skin had turned a shade of blue until an old friend came to visit and was surprised by his change in appearance.
"And he looks at me and he says, 'What have you got on your face?' 'I don't have anything on my face!'" Karason told ABC News five years ago.
"He says, 'Well, it looks like you've got camouflage makeup on or something.' And by golly, he came in and he was very fair-skinned, as I used to be."
"And that's when it hit me."
In those first months, Karason didn't notice a change in his skin color. But there were changes in his health, he says, and they were positive ones.
"The acid reflux problem I'd been having just went away completely," he said. "I had arthritis in my shoulders so bad I couldn't pull a T-shirt off."
"And the next thing I knew, it was just gone."
As for whether it was the colloidal silver that had cured him in spite of the skin poisoning, Karason said, "there's not the slightest doubt in my mind."
As recently as the 1950s, colloidal silver was a common remedy for colds and allergies, so buying into the idea might not have sounded crazy then.
Karason became an Internet sensation, perhaps the most famous in recent times of anyone who has blue-shaded skin, although he is far from alone.
The most notorious - the Blue Fugates of Kentucky - lived in an isolated pocket of Appalachia, passing down a recessive gene that turns skin blue.
Doctors don't see much of the rare blood disorder today.