This is about something you sense in yourself or others that is moved by other than human and conscious motives. It is like being asleep and sleep walking, there is no sense of any response there. Or at least they are moved by urges that control them and they are controlled by. This is something like we meet when we see people moved by habits, by propaganda, by religious bigotry or political brain-washing.
In a sense we are all zombies, or have a part of us that is a zombie. It is because we are all programmed and what we do is not from our real selves. If you find it difficult to believe read Programmed and childhood