His books like KOKO are brilliant for me. I like serial killers, although I prefer serial killers with a supernatural angle. KOKO almost gave the killer a supernatural feel to him. A sense that he was the devil.
I once tweeted Straub asking if he knew about COCO the Spanish boogeyman.
He said no.
https://en.wikipedia.org/wiki/Coco_(folklore)
HOUSES WITHOUT DOORS is superb btw. The vignettes at the start and end of the book had an effect on me so wild. I cannot explain how they did that.