Jeff VanderMeer's Annihilation is a novel (part one of a trilogy) which tries very hard to evoke a creepy atmosphere. It didn't work on me, but your mileage may vary.
The extremely untrustworthy first-person narrator serves as the primary tool for executing and implementing the extreme creepiness of the atmosphere. But the narrator is so extremely untrustworthy that she barely gets to explain what is going on in the novel --- she keeps interrupting her own narrative with exclamations about her untrustworthiness, with flashbacks about her undependable memory, with second-guesses of her own first-hand experiences. If this was excised, the novel would be a lot shorter and less interesting (like watching Memento in the right order).
Ok, so the untrustworthy narrator (one of my favorite tools, when executed subtly and well) didn't make it creepy. What about the setting, the monsters, the story?
They just didn't catch me enough to be creepy. The narrator and the emotional timbre of the entire novel were a little too distant to have any emotional hook. It just seemed... remote. Why should any reader care about the story, when even the narrator gets disassociatively bored at the climactic parts and switches to describing something else? (And as a perpendicular complaint: there was simply not enough hard science in this novel, for a narrative that supposedly came from a scientist's mind.)
Yes, I realize this is all part of a more carefully structured trilogy. Many reviewers say that book 1 makes a lot more sense, re: narrative jumps and avoiding descriptions, after reading book 3. But my time is finite and this just didn't entice me enough to pick up the following novels in the series.
This post's theme word is lysergic, "trippy, psychedelic" --- but often used to describe natural panoramas of beauty and majesty, in my reading experience. The swampy and forested expanses rolled out before her in lethargic, lysergic beauty.