I am an egg that contains a palace, or rather, I am a palace that has been contained in an egg.

I am a marvel made into a miniature so that I can travel between worlds.

If you were to discover me in the underworld and take me to the upper world, you would find that I am a palace you can enter. You may take from me what will best serve.

That is all I can say. To say anything more would be to give my secrets away.

Magic Egg in The Norka, Russian Fairy Tales Collected by W.R.S. Ralston. Egg by Faberge.

Imagine that you had this magic egg that you found in the underworld. When you expose it to the air, a palace appears. You can walk into the palace and bring something out that is useful and perhaps even urgently needed by the world at this time. What would you go looking for? Where in the palace would you find it? Take fifteen minutes to write your story.