Burn Watch
What’s the Shifting Hallway? It’s located at the end of the Fortune Hall in Sylvaren where you are met with a series of 4 doors to enter.
Enter in the correct order and you can exchange a familiar for a new one!
Codes change every Monday, so once you crack the code for the week, you can return again the next day to receive another familiar up until the Sunday night rollover to Monday.
I will post the code here if I know it! If you crack the code and would like to contribute to the thread, feel free to post before as well 
Below is a direct link to the hallway:
https://www.sensipets.com/fortune-hall/shifting-hallway