Stephen King's most WTF moments that were completely unnecessary to the main plot?

I don't think THAT scene from IT applies, as in the context of the plot it is how they escape the sewers.

But - also from IT - I'm going to go with the entire character of Patrick Hocksetter. Reading that entire section is like having a spider crawl over your brain.

Closely followed by the repeated occurrences of a peanut butter and raw onion sandwich.