That is interesting. The Wikipedia article mentions that stimulating the left temporoparietal junction can create the illusion of a shadow person. It also mentions other possible natural causes of hallucinations, among other things. What interests me most is that I am sure you can stimulate parts of my brain that will bring on hallucinations of my mother, my dog, and the Grand Canyon. Despite this, those things are real. So I don’t see how finding areas of the brain that can produce hallucinations rules out the possibility that shadow people are real.