Apparently the party of kids that ventured into the Wonka factory lost one of their number before the book ever saw print: Miranda Piker. Her encounter with some spotty powder turns into a very bad day for her family. Not sure how I missed this first time around, but this is definite Dahl territory: wacky and mostly disturbed.
And by the way, if you only know Dahl's children's stories, you need to grab his short stories, which--incredibly and sadly--appear to be out of print. Here's an omnibus edition you can snag used.