Related Clues:

• ''Hamlet'' prop
• Brain container
• Jolly Roger's image
• Brain protector
• Trepanation pokes holes in it
• The head-bone
• There's a bra in the inside of this
• Sound of blade in head
• Bony frame of head ...
• Part of skeleton
• Brainbox
• Head as a skeleton
• A nutcase?
• Hard head?
• Pirate flag depiction