OK, I almost have my 3rd builder to the Master Builder stage and I just gotta know...what the heck is in the box it takes three Master Builders to bust in to??

It's a piece of the gong.

BTW, could you put "spoiler" in this title's thread please?

That crate drove me crazy - I so much wanted to know what was inside it. And then one master builder couldn't open it. So I worked and worked and then I got the vines cleared - then I had an idea what was in the crate. Was a bit of a letdown for me. Useful, but not interesting, the way some other things are.