Yes i think they are real, and i dont want to fright you, but if they are were dangerous, then your the children would be dead by now. The point is that "they" attach to children because children are not polluted with fear, they are pure, innocent and adults not. How and why on children? I dont know either, but i only know that i heard those stories before. And another thing is, they use dreams to communicate or to show similations what happened in the past or future. That saying those dreams could be a memory.