I love eldritch horror, but I think it's hard to write it in an original way. HP Lovecraft's monsters pretty much defined the genre, which is why we see a lot of massive underwater monsters full of tentacles as eldritch abominations. On the other hand if you go too far in the direction of incomprehensible horror and alien geometries it can get a bit too abstract and confusing.
I just want to preface this with the caveat of I'm mostly a hobbyist and my, like, Actual Factual Education on this shit is kinda sparse and is subject to correction by people going HOOOLD OOON TEN but
anyway:
I think the main issue with this is that you're confusing the common aesthetics of the genre with the real meat of the stuff. Cosmic horror is more than Cthulu and even the big guy's real terror in the context of the story is not, necessarily, that he's a big fuck-off kaiju but rather that his existence upends everything you thought you knew and took for granted about the universe. Humans are the pinnacle of existence? Lawl. There's a kind and loving God? Nope. Anything in your small, insignificant life really mattering? Come on, he's just going to actually wake up at some point instead of blearily fumbling for his alarm clock and that's it. Lights out civilization. It's...about that sense of uneasiness. That kind of queasy vertigo as your worldview comes unmoored and why the imagery of the ocean and of space is so closely associated with it I think (beyond, y'know, most writers being unimaginative hacks). Water is the closest you can get to the idea of unformed chaos. A lot of ancient texts use the sea or the ocean as an allegory for what the world was like being the World proper began and it makes sense. It's clearly
something but it's unformed. It's inconstant. It flows and pours and it's endless and it's
deep.
Deep beyond all measure, beyond all imagining.
Anything could be lurking in that deep and how would you know? How would you be able to tell?
I guess in a roundabout way what I'm saying, and why Lovecraft's visions are partially so enduring, is because of the idea behind it. The idea that nothing that was ever important to you really matters in the face of such unimaginable age, such power, such alien
will. You are just a small blotch of meat adrift on a little mote of dust in a universe that yawns empty and hungry and bigger than you could ever comprehend. Your ideas of what's important, your image of what you actually
are, would be cute if it wasn't so small and sad and meaningless.
Cosmic horror is kinda hard to work with though because it's bleak as
fuck and is explicitly geared around a large loss of agency. It's hard to do well, it's easy to botch, and for all that it's evocative it's not something that usually gels well in high concentrations. In that context (and again, amateur stabs in the dark here) what you identify as eldritch horror is sort of a derivative of that. Something that takes the trappings and scales it down, or masks it in something else. Directs the focus elsewhere.
...Mostly I'm just trying to think of a way to shill
Intruders: Encounters with the Abyss here.
I really wouldn't say that it's cosmic horror exactly, there's ways to manage basically everything in the book, but it probably suits your idea of eldritch horror pretty well and has good rules on writing horror all around. One of the most important ideas is that horror needs to be
personal. The damage it does needs to mean something significant for the main viewpoint in question. Which seems like a weird thing to say after waxing on a bit about how cosmic horror is all about Nothing Really Mattering and we're all going to turn into Deep Ones anyway so whatever but bear with me.
Cthulu waking up in a thousand years and obliterating human civilization is an abstract kind of scary. It's too big, too far off, too distant to get a handle on. A sailor losing his grip on his sanity as his world unravels is much more visceral and much more unsettling. For all its big ideas, at the end of the day cosmic horror needs to be filtered through a personal lens if you get what I'm saying.
Horror is all too often about xenophobia, and I'm more of a xenophile myself. I'd usually rather read about human/alien first contact and interspecies romance than humans and aliens killing each other or being horrified by each others' alienness.
Well yeah but that's mostly a function, I think, of (well for one writer's being hacks) but also the general rule that the scariest shit is what you don't know. What you don't see, what you can't process, what you don't understand. A serial killer standing across from you in a brightly lit room where you can go "yup, that's a dude in a pig mask" is less scary than your kindly next door neighbor staring dead-eyed at your bedroom window at 3 am as he slowly rips up and eats your mail with a smile.
The first has dimensions, easily determinable threat level, it's something you can understand. The second throws the brain for a loop and doesn't have a clear basis for explanation, and in the absence of facts or firm grounding the brain fills in increasingly dire shit.
