What it is, only God knows. In terms of matter I suppose the thing Ammi described would be called a gas, but this gas obeyed the laws that are not of… - H. P. Lovecraft

Shreiking, slithering, torrential shadows of red viscous madness chasing one another through endless, ensanguinated condors of purple fulgurous sky... formless phantasms and kalaidoscopic mutations of a ghoulish, remembered scene; forests of monstrous over-nourished oaks with serpent roots twisting and sucking unnamable juices from an earth verminous with millions of cannibal devils; mound-like tentacles groping from underground nuclei of polypous perversion... insane lightning over malignant ivied walls and demon arcades choked with fungous vegetation...

No book had ever really hinted of it, though the deathless Chinamen said that there were double meanings in the Necronomicon of the mad Arab Abdul Alhazred which the initiated might read as they chose, especially the much-discussed couplet:

There are not many persons who know what wonders are opened to them in the stories and visions of their youth; for when as children we learn and dream, we think but half-formed thoughts, and when as men we try to remember, we are dulled and prosaic with the poison of life. But some of us awake in the night with strange phantasms of enchanted hills and gardens, of fountains that sing in the sun, of golden cliffs overhanging murmuring seas, of plains that stretch down to sleeping cities of bronze and stone, and of shadowy companies of heroes that ride caparisoned white horses along the edges of thick forests; and then we know that we have looked back through the ivory gates into that world of wonder which was ours before we were wise and unhappy.