Only a specific sequence of steps will allow access to its secret compartment. Check out the YouTube video to see it in action. Made up of 36 separate pieces, it all snaps together to complete the finished product.
Because of the number of parts and the complicated assembly, I created a few aids to help out. I've included a parts list and a part identification guide, plus created a special YouTube video detailing the assembly process. Printing all of the pieces requires about 150 hours of printing and lots of PVA support material. I suggest watching all or part of the assembly video prior to starting to print to make sure you really want to take this on.
In the parts list, I included the brand, type and color of the filaments I used. Of course, you can use anything you want to print it, but I would suggest using the same material types that I used (Nylon, PLA, ABS, TPU) to maintain the same part interactions and flexibility.