Rumpelstiltskin

"I will give you three days," he declared. "If by then you can guess my name, you can keep your child."

All night long the queen racked her brains, thinking of all the names she had ever heard. She dispatched a messenger to inquire throughout the land if there were any names she had forgotten. When the little man returned the next day, she began with Casper, Melchior, and Balthasar and recited every single name she had ever heard. But at each one the little man said: "that's not my name."

The next day she sent the messenger out to inquire about the names of all the people in the neighbourhood, and she tried out the most unusal and bizarre names on the little man: "Do you happen to be called Ribfiend or Muttonchops or Spindleshanks?" But each time he replied: "That's not my name."

On the third day the messenger returned and said: "I couldn't find a single new name, but when I rounded a bend in the forset at the foot of a huge mountain, a place so remote that the foces and hares bid each other goodnight, I came across a little hut. A fire was burning right in front of the hut, and a really strange little man was dancing around the fire, hopping on one foot and chanting:

'Tomorrow I brew, today I bake,
Soon the child is mine to take.
Oh what luck to win this game,
Rumpelstiltskin is my name.'"

You can imagine how happy the queen was to hear that name. The little man returned and asked: "Well, Your Majesty, who am I?"

The Queen replied: 'Is your name Conrad?"
"No, it's not."
"Is your name Harry?"
"No, it's not."
"Could your name possibly be Rumpelstilstkin?"
"The Devil told you that, the Devil told you!" the little man screamed, and in his rage he stamped his right foot so hard that it went into the ground right up to his aist. Then in his fury he seized his left foot with both hands and tore himself in two.

From Rumpelstiltskin, in Maria Tatar's The Annotated Classic Fairy Tales