The Mythology & Folklore Database
When the day was about to dawn, the elves said to the man, "You're a very jolly companion, and must come out and have a dance with us again. You must make us a promise, and keep it."
So the elves, thinking to bind the man over to return, took a large wen that grew on his forehead and kept it in pawn; upon this they all left the place, and went home.
The man walked off to his own house in high glee at having passed a jovial night, and got rid of his wen into the bargain. So he told the story to all his friends, who congratulated him warmly on being cured of his wen. But there was a neighbor of his who was also troubled with a wen of long standing, and, when he heard of his friend's luck, he was smitten with envy, and went off to hunt for the hollow tree, in which, when he had found it, he passed the night.
Elves, mistaking him for their former boon-companion, were delighted to see him, and said, "You're a good fellow to recollect your promise, and we'll give you back your pledge."
So one of the elves, pulling the pawned wen out of his pocket, stuck it onto the man's forehead, on the top of the other wen which he already had. So the envious neighbor went home weeping, with two wens instead of one.
This is a good lesson to people who cannot see the good luck of others, without coveting it for themselves.