Everyone knows there are frost giants and trolls in the mountains, but the existence of trolls in caves isn't such common knowledge these days. And they can be as bad as mountain trolls, let me tell you. Here's a story to show you what I mean.
The Cave Trolls of the East were tired of living in darkness. Caves don't have windows, after all. Of course, being trolls, they couldn't go out in the sun anyway, but they were envious of the other creatures of the wild, who could see or sleep as they pleased, with bright colors in summer and glowing snow in winter to greet them. The cleverest group of trolls, they were three as these groups often are, came up with a plan. They would bring the flying stars of the forest to their cave and have lights around them all day. The colors would have to be figured out later.
A group of trolls trooped out of the cave, after sunset, when it was safe. They started to catch the flying stars, and they had so much fun, and the stars were so beautiful, that they didn't stop until they had caught every one in the forest. Then they returned to their caves with their prize. It didn't take long for everyone to notice the stars were gone. Not sure what to do, some people made a sacrifice to Odin to ask him for wisdom. Odin had to ask his friend Mimir what had happened (the gods were celebrating a good crop of barley, if you know what I mean) and when he was told, Odin was not pleased. He took his form as an old man in a dark cloak and he went to the trolls' cave. He knocked at the door just as dusk was falling and several pairs of eyes lit up in the dark. "Hello!" Odin called, "Can somebody help an old man in need of shelter for the night?"
Now, we think that trolls are hateful and selfish, but that's because we normally meet them in the mountains where they are poor and have nothing. Cave trolls often live comfortably, except for the darkness, and they are generous to travelers, up until they eat them.
These trolls were happy to invite Odin in, not recognizing him. They gave him mead and bread and stewed eagle eggs. Then they asked him if he wanted to see the treasure. In the past, they just took their guests to a dark corner of the cave, knocked them on the head, and dumped them in the stew pot. But now, they really had a treasure and they wanted to show it off. The cavern was full of stars, bright and shining, and all the trolls gazed at them in wonder. Odin felt a little sorry that he had to take the stars away, but take them he must.
He began by complimenting the trolls on their skills at capturing the stars and the trolls felt flattered that a strange man would be so kind. They all drank more mead and made themselves merry, and finally Odin proposed a game. "You have been good at star catching," he said, "But the stars are innocent. A man, on the other hand, is wily. Do you think you could catch me if I hid in your caves?" The trolls grasped their sides and gruffawed. Of course they could find him. These were their caves, after all. And they were used to roaming around in the dark. They all closed their eyes to give the man a sporting chance, and when they weren't looking, Odin took out his great sack and gathered all the stars inside. Then he fled the cave with them, just making it out when the howls began.
Now it was dark, so the trolls could give chase. Odin could not rest a moment that night. In the morning the trolls had to hide in gullies and burrows and Odin tried to continue. As a man he was weak, and he couldn't recover his godly form as the mead of the trolls blocked his powers. Finally he could go no further and he sank down under a tree to rest. Soon, he was asleep.
Even gods in human form are not aware of everything, and Odin had not noticed the two children playing among the trees. Neither did he notice his crows, Hugin and Munin, come to guide him home to Asgard. The crows screeched until the children looked over and then they noticed the sack. Cautiously, the children came closer. They took the sack and peered inside, and were enchanted to see the stars glowing happily. In an instant they forgot about the old man napping against a tree in the forest and they ran home with a sack of stars.
Although the village folk were awed by the stars, they did not know what to do with them. They could not start fires and people are so used to light that they are not impressed by stars in their homes, like the trolls were in their cave. Nobody paid much mind to the children and the sack, until that night when a storm arose. "'Tis the trolls of the caves!" some said, and they told the children to throw the sack of stars to the forest to show the trolls the way home. The children refused, and with a crash of thunder, the door to the big house flew open. Odin was beginning to feel his godliness again, and even though he was still an old man, he was larger than most and had a feel of electricity about him. He stomped into the house and snatched the sack from the children gruffly. But, before he went back into the storm, he turned and said to them, "You have kept the stars safe, and your village I will keep safe from now on." Then the door slammed behind him.
Odin knew that if he let the stars free in the forest the trolls would just catch them all again, so he told the stars to fly higher than they had ever flown and opened the sack. The stars rose, quickly to the tree tops, slowing down as the rain swished over them, then fast again as they reached the roof of the sky. The stars stuck to the sky and were out of the reach of the trolls forever. But they gave them light in the forest, and that was enough.