And now she went continually onwards, far, far to the very end of the world. Then she came to the sun, but it was too hot and terrible, and devoured little children. Hastily she ran away, and ran to the moon, but it was far too cold, and also awful and malicious, and when it saw the child, it said, “I smell, I smell the flesh of men.” On this she ran swiftly away, and came to the stars, which were kind and good to her, and each of them sat on its own particular little chair. But the morning star arose, and gave her the drumstick of a chicken, and said, “If you thou hast not that drumstick thou canst not open the Glass mountain, and in the Glass mountain are thy brothers.”
The maiden took the drumstick, wrapped it carefully in a cloth, and went onwards again until she came to the Glass mountain. The door was shut, and she thought she would take out the drumstick; but when she undid the cloth, it was empty, and she had lost the good star’s present. What was she now to do? She wished to rescue her brothers, and had no key to the Glass mountain. The good sister took a knife, cut off one of her little fingers, put it in the door, and succeeded in opening it.
The Seven Ravens - Brothers Grimm
One of my favorite fairy tales when I was little.