How to stop a ghost in my dream?

During the Gran Chaco War, 1928-1935 between Paraguay and Bolivia. ( we isted the Bolivians in intelligence gathering) I had occasion to decapitate a rather cheeky fellow who refused to speak. Since this time he visits me in my sleep two or three times a week. His head floats into my dream and he rolls his eyes in an immature manner, sticks his tongue out making a stupid childish noise and says " ha, you didnt expect this did you? " How do I ban him from entering my head what?