CarlBass on Instructables (who's also the CEO of Autodesk) created a 3D modelled, laser-cut version of his son's head, designed to have a secret compartment instead of brains.
We made a box in the shape of my son’s head. We laser cut pieces of taskboard (corrugated cardboard works well, too) and laminated them together. The heads pivots on a dowel and is held in place by two magnets... Round magnets have been added on the top and bottom of the head so it snaps close and conceals the secret hiding spot.