- "[The flying polyps were a horrible elder race of half polypous, utterly alien entities... They were only partly material and had the power of aerial motion, despite the absence of wings... [They exhibited] a monstrous plasticity and ... temporary lapses of visibility... [S]ingular whistling noises and colossal footprints made up of five circular toe marks seemed also to be associated with them."
- ―H. P. Lovecraft, "The Shadow Out of Time"
The flying polyps (also called Elder Beings or Polypous Race) came to Earth out of space as conquerors about seven hundred fifty million years ago. They also inhabited three other planets in the solar system, including possibly Yaksh (Neptune) and Tond (though Tond itself may lie outside the solar system, or may be possibly referring to Pluto, which was discovered only 6 years before the publication of the story). On Earth, they built basalt cities with high windowless towers. When they attempted to colonize the oceans, the polyps were driven back by the Elder Things. Thereafter, they restricted their habitats to the surface world.
Their senses did not include sight, but what senses they had could penetrate all material obstructions. They were only partially matter, but still solid enough to affect and be stopped by normal materials; this additionally gave them resistance, if not outright invulnerability, to normal means of damage, though they could be destroyed by certain forms of electrical energy. Their minds were so strange that the Great Race of Yith could not perform psychic transfers with them.
They are able to levitate and fly despite lacking any visible means of doing so, and leave telltale massive footprints when on the ground. Their amorphous bodies can turn invisible at will, though this ability appears somewhat negated by whistling noises associated with them in general. In battle, their ability to control and direct powerful winds is put to use as a weapon.
When the Great Race of Yith came to Earth, they warred with the polyps and soon drove them underground with their advanced technology. The Great Race then sealed the entryways to the polyps' subterranean abode with trapdoors, which afterwards were diligently guarded. The polyps' cities were left abandoned, perhaps as a reminder of the horrors that dwelt below.
Eventually, the polyps rose up and exterminated the Great Race, afterwards returning to their subterranean haunts. Having no conception of light, the polyps seem content to remain there, annihilating the few intruders that chance upon them. The entrances to their dwellings are mostly deep within ancient ruins where there are great wells sealed over with stone. Inside these wells still dwell the polyps.