THE GREAT OLD ONES
As aforementioned, The Space Between The Stars and The Great Old One exists since the beginning of our current spacetime cycle. For this reason, all beings in our consensus reality universe share subbiological, subquantum characteristics with The Great Old One: They can interbreed. Which means that, for example, a human female can be impregnated by an emanation of The Great Old One. The offspring of such abhorrent intercourse will be more than "alien" for human eyes and mind, though; not to mention the sexual act itself which has nothing to do with anything we usually perceive as sex or even as biological. We chose one particularly explicit literary depiction to illustrate the spawn of transdimensional fornication with the Great Old One's pocket universe projections. It's from "The Dunwich Horror", written in 1928 by H.P. Lovecraft:
"The thing that lay half-bent on its side in a foetid pool of greenish-yellow ichor and tarry stickiness was almost nine feet tall, and the dog had torn off all the clothing and some of the skin (...) It would be trite and not wholly accurate to say that no human pen could describe it, but one may properly say that it could not be vividly visualised by anyone whose ideas of aspect and contour are too closely bound up with the common life-forms of this planet and of the three known dimensions. It was partly human, beyond a doubt, with very manlike hands and head, and the goatish, chinless face had the stamp of the Whateleys upon it. But the torso and lower parts of the body were teratologically fabulous, so that only generous clothing could ever have enabled it to walk on earth unchallenged or uneradicated. Above the waist it was semi-anthropomorphic; though its chest (...) had the leathery, reticulated hide of a crocodile or alligator. The back was piebald with yellow and black, and dimly suggested the squamous covering of certain snakes. Below the waist, though, it was the worst; for here all human resemblance left off and sheer phantasy began. The skin was thickly covered with coarse black fur, and from the abdomen a score of long greenish-grey tentacles with red sucking mouths protruded limply. Their arrangement was odd, and seemed to follow the symmetries of some cosmic geometry unknown to earth or the solar system. On each of the hips, deep set in a kind of pinkish, ciliated orbit, was what seemed to be a rudimentary eye; whilst in lieu of a tail there depended a kind of trunk or feeler with purple annular markings, and with many evidences of being an undeveloped mouth or throat. The limbs, save for their black fur, roughly resembled the hind legs of prehistoric earth's giant saurians, and terminated in ridgy-veined pads that were neither hooves nor claws. When the thing breathed, its tail and tentacles rhythmically changed colour, as if from circulatory cause normal to the non-human side of its ancestry. In the tentacles it was observable as a deepening of the greenish tinge, whilst in the tail it was manifest as a yellowish appearance which alternated with a sickly greyish-white in the spaces between the purple rings. Of genuine blood there was none; only the foetid greenish-yellow ichor which trickled along the painted floor beyond the radius of the stickiness, and left a curious discolouration behind it."