Nope, my kids have absolutely no idea who The Boogie Man is. DS4 does know about ghosts and monsters and skeletons. In fact, the book we got DS about the anatomy of the human body has to be stored in mine and DH's room because DS doesn't like having the "bone book" in his room at night. And DS has occasionally woken up complaining of "monsters outside". When I do this, I assure him that there are no monsters outside -- just deer and coyotes and squirrels.