A character in Lovecraft's tale "The Call of Cthulhu". Cthulhu is a monstrous entity who lies "dead but dreaming" in the city of R'lyeh, a place of non-Euclidean madness presently (and mercifully) sunken below the depths of the Pacific Ocean. Cthulhu appears in various monstrous and demonic forms in early myths of the human race. Racial memory preserves Him as humanity's most basic nightmare. Cthulhu is the high priest of the Great Old Ones, unnatural alien beings who ruled the Earth before humanity formed, worshipped as gods by some misguided people. It is said that They will return, causing worldwide insanity and mindless violence before finally displacing humanity forever.

High priest of the great "Old Ones," alien super-beings who came to earth many millions of years ago during the Paleozoic era that were eventually worshiped as gods by the johnny come lately human race.

His name is unpronounceable by human mouths.

A rough description of Cthulhu goes as:

A pulpy, tentacled head surmounted a grotesque and scaly body with rudimentary wings ... It 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. This thing, which seemed instinct with a fearsome and unnatural malignancy, was of a somewhat bloated corpulence ...

A entity for H.P. Lovecraft's short story "The Call of Cthulhu" who also appears in several later stories, though CC is the only one that focuses on him. Cthulhu is a extraterrestrial being referred to as "Great Old Ones" and is generally associated with madness. It is said to have "yielded simultaneous pictures of an octopus, a dragon, and a human caricature.... A pulpy, tentacled head surmounted a grotesque scaly body with rudimentary wings." While no specifics of it's height have been given, in the Climax of Call of Cthulhu, when some sailors stumble upon the formerly-sunken city of R'lyeh, the city in which Cthulhu is said to be sealed, they accidentally release the monster, and one said it was "A mountain that walks or stumbles", implying it's enormous height.

For some reason, Cthulhu along with the other Great Old Ones have been sealed away, and is said that Cthulhu one day will awaken and release the Great Old Ones and they will resume the rule of Earth, and there will be a "Holocaust of freedom and ecstasy". the Great Old Ones telepathically talked with the earliest humans, and started the infamous Cult of Cthulhu.

many real life cults have been started and can be found on the internet. I'm not sure which scares me more, the Cthulhu cults, or the other religions.

A big fuckin' octopus

He who lies dead but dreaming. He who lies waiting under the waters, ever seeking entrance into the world of the living, so The Ancient Ones may rule the Earth once more.

A fictional character created by H.P Lovecraft a horror writer in 1919. Cthulhu is described as " A thing too horrible to describe." Although it is often though of having an octopus-like head, with bat-like wings, and being the size of a mountain. The very sight of Chthulhu can bring a grown man on his legs, and cry like a baby.
There are nut jobs out there, REALLY OUT THERE that worship it.

I find the concept of Cthulhu, and the cults....a little freaky.

The Great Old One, or High preist of the Great Old Ones depending on the story you read.
Less a god than a monstrous horror resembling an octopus, man, and dragon cojoined from a creation wholy unlike birth.
Best pronounced sucking water into your lungs whilst beining dragged down by a tentical.
Anyone shewn Cthulhu, sometimes even in representations fearfully crafted by his cults, cannot survive sane.

Our merciless, great and humble god. Deserves many human sacrifices. The ultimate head giver. Those who oppose the will of Cthulhu will receive dreadful, yet merciful punishments (no head)

Cthulhu is the great almighty Lord. For he is our saviour and our great master. NLM (no lives matter) was created in service of him