COLOURS OUT OF SPACE

The colours out of space are an alien lifeform that sucks life out of all living things. Their exact nature and form is unknown. The only documented appearance of the species happened when a meteor  fell in a rural area west of the  town of Arkham, Massachusetts, landing next to a well, on farmland belonging to one Nahum Gardner in 1927. The meteorite possessed odd properties:

• It wastes away when exposed to natural air.
• It continuously produces significant amounts of heat.
• It is unusually soft for something resembling rock.
• No noticeable gases released when heated over charcoal.
• No reaction to the borax bead test.
• No apparent reaction to any producible temperature, including that of the oxy-hydrogen blowpipe.
• Highly malleable.
• Luminous. Especially noticeable in dark surroundings.
• Spectroscopic analysis during heating resulted in shining bands unknown previously in the visible spectrum.
• Mostly immune from reaction to all laboratory-standard agents. Small and faint traces of Widmansättten pattern appear on it in response to acid agents.
• Generally accepted to be a metal of some sort.
• Possesses the qualities expected of a magnetic material.
• Affinity for electricity, to the point where it could divert lightning strikes to itself.
• Damaging to silicon compounds.

The colours inhabit small colored, fragile globules within such meteors, exhibiting the odd band of colors described above. A simple hammer tap is sufficient to break one open, resulting in no noticeable release of anything at all.

The colours possess mutagenic properties. In its presence, the plant life started turning brittle, growing smaller than normal, growing increasingly more hideous-looking, gray, and in the case of the crops, bitter and sour or a the best, tasteless. The insects followed suit, dropping dead rapidly. Animals in the area are also affected, their bodies, behavior and activity showing hints of alteration, such as leaping distances well above their normal capability and malformed body proportions and appearances. Cows grazing on grass near the site produce milk of worthless quality. Horses can be driven violently mad by it. The rest of the farm animals also fell to the same fate. The poultry turned gray, rapidly died and their meat found useless as food, being dry and of disgusting taste. Hogs grew massively fat, developed isolated mutations on their bodies here and there, and then soon after turned gray and collapsed like the rest of them, their meat found unedible for the same reasons as the poultry. Cows were next, portions of their bodies, or even the entire thing, shrank incredibly. The result was the same. They turned gray and died. The vegetation thereafter began crumbling like dust into grayish powder, and it was soon discovered afterwards that the well water was of undrinkable quality. 

Source: Lovecraft [1927] (1984). “The Colour Out of Space”, 
S. T. Joshi (ed.): The Dunwich Horror and Others, 9th corrected printing, Sauk City, WI: Arkham House. ISBN 0-87054-037-8. Definitive version.
Wikipedia Entry.