Atmospheric beasts are among the strangest of ariel monsters from cryptozoology. According to eyewitness reports, they are things that seem like living creatures, but they break all the usual rules that we apply to living things. They fly without the need for wings and their bodies are only semi-solid, often partially invisible to boot.
Atmospheric beasts are very fragile and lightweight creatures who are either native to Earth or are aliens that came from elsewhere. If the latter view is taken, then atmospheric beasts are sometimes thought to have originated in the atmosphere of some other planet, but they can also be thought of as originating in interstellar gas clouds so that they are, in effect, aliens without a native planet, able to "swim" through space. Believers generally consider atmospheric beasts to be non-intelligent, so that even if these creatures did originate somewhere other than earth, they still do not count as sentient extraterrestrials, merely animals.
Atmospheric beasts can change their density, becoming smaller, harder masses that are usually metallic in color, or they can become larger and cloudlike, even to the point of invisibility. In some reports, they may glow. Atmospheric beasts may roughly resemble whales and are sometimes called air whales or cloud beasts. Believers think that the atmospheric beasts' normal habitat is high in the air, and they might die if they ever touch the ground. Atmospheric beasts that resemble clouds may engage in behavior that is thought to be impossible for a real cloud, such as squirting a stream of horizontal water at people through "lips" or being far too mobile and animate for witnesses to believe it was just a patch of fog.
It is said that when atmospheric beasts die, they fall to earth as a gelatinous mass that may resemble a green, purple, gray or iridescent jelly that evaporates into nothing within minutes, hours, or, at the longest, a few days. This is supposed to explain a type of anomalous event, pwdre ser, that puzzled scientists for some time before they decided that pwdre ser did not exist. Pwdre ser is Welsh for "rot from the stars."