Known for their strange cry "tekeli-li, tekeli-li," they are genetic creations of the Great Old Ones. They went out of control and evolved on their own. It is said by Alhazred that none were ever created on earth, probably to prevent unnatural panic in the readers of the Necronomicon. From Colin Wilson's THE OCCULT: It is interesting to note that Arthur Grimple, a land commissioner in the South Pacific Gilbert Islands wrote in his book "Pattern of the Islands, that there in Kuma village, the hereditary porpoise-callers of the High Chiefs of Butaritari and Makin-Meang. In a dream these men sent their spirit out to seek "the porpoise-folk in their home under the western horizon and invited them to a dance, with feasting, in Kuma village. If he spoke the words aright (and very few had the secret of them) the porpoise would follow him with cries of joy to the surface." Once he had contacted the porpoise, he would rush from his hut and fall on his face, then stand "clawing at the air and whining on a queer high note like a puppy's. Then words came gulping out of him: 'Teirake! Teirake! (Arise! Arise!" ... They come, they come ...'" The villagers rushed to sea and stood waist deep waiting. Then the porpoises would come: "They were moving towards us in extended order with spaces of two or three yeards between them, as far as my eye could reach. So slowly they came, they seemed to be in a trance. Their leader drifted in hard by the dreamer's legs. He turned without a word to walk beside it as it idled towards the shallows.... The villagers were welcoming their guests ashore with crooning words. ... As we approached the emerald shallows, the keels of the creatures began to take the sand; they flapped gently, as if aking for help. The men leaned down to throw their arms around the great barrels and ease them over the ridges. It was as if their single wish was to get to the beach." Then the 'hypnotised porpoises' were slaughtered and eaten.
("The Thing on the Doorstep," "The Shadow Over Innsmouth," "At the Mountains of Madness")
[See also SHOGGOTHS by Albert N. Wilmarth, published by M.U.P.]