Lovecraft describes Cthulhu as "A monster of vaguely anthropoid outline, but with an octopus-like head whose face was a mass of feelers, a scaly, rubbery-looking body, prodigious claws on hind and fore feet, and long, narrow wings behind." Cthulhu has been described as a mix between a giant human, an octopus and a dragon, and is depicted as being hundreds of meters tall, with human-looking arms and legs and a pair of rudimentary wings on its back. Cthulhu's head is depicted as similar to the entirety of a giant octopus, with an unknown number of tentacles surrounding its supposed mouth. Cthulhu is described as being able to change the shape of its body at will, extending and retracting limbs and tentacles as it sees fit.
H. P. Lovecraft's initial short story, "The Call of Cthulu", was published in Weird tales in 1928 and established the character as a malevolent entity hibernating within an underwater city in the South Pacific called R'Iyeh. The imprisoned Cthulhu is apparently the source of constant anxiety for mankind at a subconscious level, and also the subject of worship by a number of religions (located in New Zealand, Greenland, Louisiana, and the Chinese mountains) . The short story asserts the premise that, while currently trapped, Cthulhu will eventually return. His worshipers chant "Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn" ("In his house at R'lyeh, dead Cthulhu waits dreaming.")