Origin: The Dream-Quest of Unknown Kadath by H.P. Lovecraft (1943).
For they were not men at all, or even approximately men, but great greyish-white slippery things which could expand and contract at will, and whose principal shape—though it often changed—was that of a sort of toad without any eyes, but with a curiously vibrating mass of short pink tentacles on the end of its blunt, vague snout.
— H.P. Lovecraft, The Dream-Quest of Unknown Kadath
Inhabitants of the far side of the Moon in the Dreamlands, the Moon-Beasts live in windowless cities of stone. They sail black galleys between the moon and the Dreamlands, trading rubies for both slaves and gold, at the port of Dylath-Leen. When there, they employ the Men of Leng, disguised in turbans, as their go-betweens and stay hidden below deck, lest the merchants of Dylath-Leen learn the terrible secret of with whom they are dealing.