Sounds like a fertile place to find some gay subtexts.
Sure enough, at age 20, Ernst was taking a nature walk in Norway when he encountered a water sprite, or Näcke, disguised as a beautiful young man with a violin. The sprite's music almost lured him to his death.
A water sprite? Or maybe a real person who suggested an erotic encounter?
Ernst went home and painted the sprite -- actually, many different sprites over the years. The image of the beautiful young man haunted him.
Ernst kept looking for his own beautiful young man. Maybe he found one in the young art student Anders Zorn (1860-1920). In 1879 they embarked on an artistic tour of Italy, Germany, France, and Spain.
He began to behave bizarrely: he claimed that he was God, and demanded a sacrifice, like Abraham sacrificed his son Isaac. He was taken back to Sweden, where he spent the rest of his life under psychiatric supervision.
He suffered a devastating blow when his masterpiece, Strömkarlen (another water sprite disguised as a beautiful young man, top photo) was rejected by the National Museum as too risque (the water sprite's penis is visible). But Prince Eugen, the Duke of Närke, saved the day by adding it to his personal collection.
Today it can still be seen in his home in Stockholm, Waldemarsudde, now a museum (a great place for beefcake aficionados, by the way).
Wikipedia says that actor Erland Josephson is his grandson, but it's wrong. Ernst never married and had no children.