Inside Universe

“How can I explain this. It’s like a shell. We live in the soft, fleshy body of a hermit crab, endlessly walking the seabed. All matter we observe – seafood. Encapsulating that is the shell; hard, separate and a completely different world. We don’t know where it came from, but it’s there all the same.”

TVS Monthly Nanofiction Bonanza April 2017
The challenge: Write a story, exactly 55 words.
What if the universe we perceive is contained within another universe?