SOURCES:
"The Horror of the Heights" by Arthur Conan Doyle

Description: “...Floating downward from a great height, there came a purplish patch of vapor...Though fashioned of some transparent jellylike substance, it was nonetheless of much more definite outline and solid consistence than anything which I had seen before. There were more traces, too, of a physical organization, especially two vast, shadowy, circular plates upon either side, which may have been eyes, and a perfectly solid white projection between them which was as curved and cruel as the beak of a vulture. the whole aspect of this monster was formidable and threatening, and it kept changing its color from a very light mauve to a dark, angry purple so thick that it cast a shadow as it drifted between my monoplane and the sun. On the upper curve of its huge body there were three great projections which I can only describe as enormous bubbles, and I was convinced as I looked at them that they were charged with some extremely light gas which served to buoy up the misshapen and semisolid mass in the rarefied air...Its method of progression—done so swiftly that it was not easy to follow—was to throw out a long, glutinous streamer in front of it, which in turn seemed to draw forward the rest of the writhing body. So elastic and gelantinous was it that never for two successive minutes was it the same shape...The vague goggling eyes...were cold and merciless in their viscid hatred...”(“The Horror of the Heights” by A. Conan Doyle)

NOTES: The cloud jungles where these things live is inhabited by both
herbivore" and "carnivore" class creatures.

HISTORY: This story has been surpassed by technology. we fly through the upper atmosphere and beyond these days, but in Doyle's year of 1913, this stopry would have been considered SF and not Fantasy.