- Nightmare Fuel: The fate of the Gardner family is possibly one of the scariest things Lovecraft ever wrote. They and their farm are slowly devoured by an Eldritch Abomination that alters their minds to keep them from leaving and eventually drives them all completely insane, all while it literally drains the life out of every organism living there. The end result is that its prey, including the Gardners, become gray, brittle, and prone to crumbling, remaining alive and aware until they disintegrate under their own weight.
"And yet amid that tense, godless calm the high bare boughs of all the trees in the yard were moving. They were twitching morbidly and spasmodically, clawing in convulsive and epileptic madness."
- The moving trees at the climax were seriously disturbing. They're a prime example of Lovecraft's "just fundamentally wrong" sense of horror.
- The blasted heath. It's a five-acre patch of gray dust that is utterly devoid of all life, even forty-four years after the Colour's arrival. And it's slowly growing, because part of the Colour is still there, feeding. And the area is later used as a reservoir for drinking water.
- Reality Subtext: Lovecraft's grandfather, Whipple Van Buren Phillips, invested in a failed dam project, causing the loss the family fortune and eventually his life as a result of the stress. This no doubt had something to do with the inclusion of the Framing Device about the reservoir surveyor.
- Lovecraft himself noted that it was in part inspired by the Scituate Reservoir, which did involve the flooding of several towns to provide a drinking water supply.
- The Woobie: It's difficult not to feel terrible for the Gardner family - not just because of their horrible fate, but because of how helpless they are to stop it as it slowly approaches.