A while ago, I showed my four-year-old some of the surviving notebooks from my childhood, for something to do and to buck her ideas up. There was one image in particular that stuck in her mind and would be brought up out of the blue months later, usually when getting ready for bed. This one:
I remember drawing that (my dad had taken me to visit the farm, bright and early, but for some reason I'd stubbornly insisted on staying in the car while he worked for however long, so I had to entertain myself by drawing, it turns out, terrifying nightmare fuel), but I can't remember where the idea came from. It seems too messed up for a six-year-old to invent, but he has been raised on the likes of Knightmare and Beetlejuice, so I wouldn't put it past him.
On a lighter note, your child asking to colour in the "Doctor Disguise Colouring-Book!" you made in 1992 is a strange, new emotion, but a nice one.
