The Face In The Floor nightmare
I am coming to see that the sensation of the worst nightmares, a sensation that can be felt asleep or awake, is identical to those worst dreams’ form itself: the sudden intra-dream realization that the nightmares’ very essence and center has been with you all along, even awake: it’s just been… overlooked; and then that horrific interval between realizing what you’ve overlooked and turning your head to look back at what’s been right there all along, the whole time….
Context
The theme's thesis sentence, delivered first person (almost certainly Hal, never named): nightmare defined not as content but as form — the overlooked thing already present, and the interval before you turn to look. It applies to the whole novel's structure, which keeps burying its horrors in plain sight. The mid-sentence "just been… overlooked" and the four-dot close are as the raw has them.