I Am A Tale In Childrens Minds I Keep Their Secrets And Share Them Inside

Riddle: I am a tale in children’s minds. I keep their secrets and share them inside. I blur their thoughts into fantasies kept Like a canvas of art or a submarine depth.Though an illusion, it occurs every night; I give them a fantasy; I give them a fright. Nor good or bad, but always nigh’ Its interesting to tell. What am I?
Answer: Dream