Does This Remind You of Anything?: Many of the effects of the Colour out of Space, such as slowly killing any life near it and contaminating the underground water supply, are similar to the effects of prolonged exposure to radiation. This is interesting given that radiation poisoning was not well known at the time Lovecraft was writing, making this a horror version of Harsher in Hindsight.
Also, Cherenkov radiation (an electromagnetic phenomenon wherein charged particles exceed the speed of visible light through a dielectric medium such as water) is known for its eerie blue color—a color not found anywhere else in Earth’s natural environment.
Ending Fatigue: The story could reasonably end after Nahum's death. Instead, it continues for another ten or so pages in which things are needlessly explained and the titular color leaves for no reason.
Hilarious in Hindsight: The plot progression has many similarities to The Lorax, of all stories. Good luck taking it seriously with that in mind!
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.
Ammi as well. The poor guy tried to support his friend, only to be forced to kill his friend's wife and watch his friend turn to dust in front of him. And when he does the good deed of informing the authorities, he ends up trapped inside the house as the color drains any life left on the acres before leaving for space, resulting in the death of his horse and a life-long trauma. And the worst part? The narrator implies that Ammi shows the same symptoms as the Gardners, thus fearing that the old lonely man will suffer the same horrible fate.
