Cthulhu is said to be
"a thing that cannot be described".
To look upon him is to be driven insane.
Some of the most detailed descriptions of Cthulhu come from statues of the Deity.
One, constructed by an artist after a series of baleful dreams, is said to have...
“...yielded simultaneous pictures of an octopus, a dragon, and a human caricature ... A pulpy, tentacled head surmounted a grotesque and scaly body with rudimentary wings."
Stephen Hickman's Cthulhu Statue on display at the The Hay Library of
Brown University of Providence.".
Another, recovered by police from a raid on a cult, represented...
"...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.”