In almost every way, J.R.R. Tolkien’s “The Passage of the Marshes” presents a deeply frightening and suffocating experience for the reader, as the two Hobbits and the decrepit Gollum move across a landscape that has become devoid of grace… (essay by Bradley Birzer)
— Read on www.theimaginativeconservative.org/2018/05/grace-unredeemed-land-middle-earth-bradley-birzer.html
Definitely the creepiest passage in LOTR.