What is Cthulhu Mythos Anyway?

“In his house at R’lyeh dead Cthulhu waits dreaming.”
For years now, I've come across this phrase, Cthulhu Mythos, but never the definition. It must be one of those things everybody knows. Authors have been using it in articles and blog posts, often, but they've never taken the time to define it and, me being too lazy, I never bothered to research it.

From what I gathered, it's a creature and it has something to do with Lovecraft.

Let's get the important stuff out of the way. I've never heard anyone say Cthulhu so I have no idea how to pronounce it.... How fun. Dictionary.com has a definition but no pronunciation.

Well, here's how they define it:
a fictional high priest of elderly gods, sleeping in his city of R'lyeh (Dictionary.com)
I love dictionary.com but this has to be the least helpful definition ever.

The term originated from "The Call of the Cthulhu" by H.P. Lovecraft. I read the story long before I knew about Cthulhu Mythos. So, looked at it again with the mythos in mind.

First of all, I've read only two authors who could pack a story full of adjectives and make it work- Edgar Allen Poe and H.P. Lovecraft. This story was so much fun to read. I had to break out my journal and take notes. The way he uses words is brilliant.

So what is a Cthulhu?
"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, and squatted evilly on a rectangular block or pedestal covered with undecipherable characters.
The tips of the wings touched the back edge of the block, the seat occupied the centre, whilst the long, curved claws of the doubled-up, crouching hind legs gripped the front edge and extended a quarter of the way down toward the bottom of the pedestal. The cephalopod head was bent forward, so that the ends of the facial feelers brushed the backs of huge fore paws which clasped the croucher’s elevated knees." (The Call of the Cthulhu)
In layman terms, it's a creature with an octopus face and bat-like wings.
As for pronunciation:
"The Thing cannot be described—there is no language for such abysms of shrieking and immemorial lunacy, such eldritch contradictions of all matter, force, and cosmic order."(The Call of the Cthulhu)
In other words, there is no one way to pronounce it. By the way, Cthulhu has to be the hardest word to type.

Cthulhu Mythos is a:
"term coined by the writer August Derleth to describe the shared themes, characters, and elements in the works of H.P. Lovecraft, his proteg├ęs, and writers influenced by him. Together, they form the mythos that authors, writing in the Lovecraftian milieu, have used—and continue to use—to craft their stories." (Wikipedia)
Understanding this turned out to be a bigger undertaking than I thought. Cthulhu Mythos is not something you can explain in a couple of words. In order to really understand it, you need to do some significant research.

I had more fun researching this than I expected. It's still amazing how a work of fiction, something that isn't real, can have such an impact on real life.

It reminds me of a study I read last year.
"When you 'lose yourself' inside the world of a fictional character while reading a story, you may actually end up changing your own behavior and thoughts to match that of the character..." (Ohio State University)
Makes you proud to be a writer. ;)

Further Reading:
Wikipedia: Cthulhu Mythos
The H.P. Lovecraft Archive-Popular Culture: The Cthulhu Mythos
Goodreads: Popular Cthulhu Mythos Books
Know your Meme: Cthulhu