Revealing mistake: Just after Rey catches BB-8, she looks back at the sand worm. Suddenly, in this shot, you can see the rigging seam on its neck where it connects to the upper part of the mouth, which is not visible in other shots. Usually, the neck seam blends in or is not visible, but in this shot, you can see where the neck and top of the mouth are separate pieces in this 2D rig. (00:01:59)