07-26-2016, 03:00 AM
I would say that a shared nightmare person would only become 'real' if it became 'persistent'; that is to say, the nightmare could form memories and retain them from day to day as an independent entity. If the nightmare retains memories and other characteristics when it appears in several peoples dreams, then it could be considered a separate entity from all of the dreamers. I would expect a group mind to create and share a number of consistent intelligent agents, memory assistants and skill modules; similar agents created by their collective dreaming subconscious minds could be more random and more dangerous.