Uzumaki
Unfortunately, the most terrifying thing about this whole series was the animation quality drop between episodes. Trying to compress 600 pages of horror short stories into 4 short episodes inevitably leads to “PowerPoint-presentation-like” mess, which not only doesn’t evoke terror and anxiety of gruesome bodily deformities but also doesn’t causally link individual scenes and storylines. I dig the black-and-white art style though and I think that more manga adaptations should work with that.