Looking for the the title/ author of a book of illustrated "silly" children's horror from around the early 1980's. The book is narrated by an uncle / grandfather to his (children?) about a strange adventure he had as a child. He is captured by a giant witch who plans to eat him but instead they get involved in telling stories to delay the meal. The only story I can remember the details is they are watching a show on television about a bunch of large hairy monsters (much like the movie 'Critters' monsters) who have constantly snotty noses. They eat a class of school children and one keeps asking for salt. The witch and the kid both find it hilarious. Somehow he escapes but is cursed to turn into a goofy monster by night.
The illustrations have little or no bright color, mostly dark tones, can't remember how much of a text / art ratio. Short story, more on the funny side and not meant to scare.