"You enter a 10 ft. x 10 ft. room. You see Cthulhu. Roll for Initiative."

[Ankh-Morpork Guard]

My love for the Far Realm and the Elder Gods/Cthulhu creatures requires me to put them in. In fact, far back in the history of my homebrew, they actually controlled the Prime Material Plane for a few thousand years. Various cults and such exist to them in the 'current' time...though I really want to run a game where the PCs go right up and fight them just for fun.

 

[ruleslawyer]

This is the really pertinent point. I think that Cthulhoid elements are great in a D&D setting, just as Conanesque, etc. elements are; however, actually having someone/thing named Conan, Cthulhu, etc. in a game seems kinda silly. IMC, I've played up the Cthulhuesque nature of the Elder Elemental God/Ghaunadaur, and my players think of him as a sort of Lovecraftian figure (and have the appropriate fear), but I don't actually use those gods by name.

 

[Gez]

I do make good use of Lovecraftesque horrors, but never the actual Cthulhu, Nyarlo, Hastur, Shudde-Mel and co. They've been the topic of too much parodies and jokes, it would ruin the ambiance more than it would help it.

 

[Ankh-Morpork Guard]

I think that Cthulhoid elements are great in a D&D setting, just as Conanesque, etc. elements are; however, actually having someone/thing named Conan, Cthulhu, etc. in a game seems kinda silly.

I can understand that...though I don't think its really any different than using the Greek Pantheon in the campaign instead of completely made up Gods. My homebrew uses tons of Gods from different cultures mixed with more generic fantasy Gods and it works just fine without being silly...Cthulhu and the Elder Gods are really just another Pantheon, in a way.

Conan, though, is a bit different. That seems more like taking someone like Elminster and dropping him into a completely different world...that doesn't really work as much as moving Gods does, IMO.

 

[HellHound]

Yes, as deities in one of my campaigns (files attached - I wrote them up back when 3.0 was first released, long before the release of CoCd20, and never updated them once later editions and books were released).

And also I've used the Shoggoth against a nearly epic party in one campaign that was a lot of fun. Scary beastie.

 

[demiurge1138]

I've done it a few times, to varying degrees of involvement and varying degrees of success. The first time, it was Cthulhu vs. Faerun, an epic-level game in which the eventual end-goal would be to stop Cthulhu from being summoned and, barring that, slay him before he reached land. There were a few memorable moments (like the Haunter in Darkness rampaging through Waterdeep), but for the most part it sucked. The inclusion of overt Mythos did break the mood a bit.

The second time was much more workable. In a Greyhawk-ish game, the players were tasked to destroy one of many cells of kuo-toa cultists, trying to create a grand ritual that would bring the Dreamlands into the Waking World permanently. The inclusion of the Dreamlands seemed to go over better than the Mythos, especially since I kept actual Lovecraft monsters to a minimum (my players now have fond memories of moonbeasts, but that was about it).

Oh, and the first game I ever DMed had a levelled-down shoggoth in a dungeon. Memorable only for how many deaths it caused and how it caused them (twisting people's heads off like bottlecaps).

Demiurge out.

 

[freebfrost]

I haven't used Cthulhu directly in a D&D game, but am currently planning a Mutants & Masterminds game crossover with Call of Cthulhu d20.

Basically, the characters will start out as 1st level CoC characters and gain their superpowers after being exposed to a meteor that heralds the coming of the Great Old Ones. By the time they are "true" superheroes they are going to get the chance to go toe-to-toe with Great Cthulhu himself!

Should be fun!

 

[Ace]

One of my players described my D&D campaign as Cuthulu 7 days a week -- Twice on Tuesday


It isn't quite that bad

 

[Desdichado]

I've used rat-things, byakhee and Hounds of Tindalos, and I did run a small town on the frontier that was fairly obviously riffing on Innesmouth, but I tend to shy away from the more well-known Mythos elements, and instead focus on more "Mythos-esque" stuff.

It's a bit hard to maintain the mystique if the players start shouting things like "it's the Big C!" and laughing when Cthulhu comes up out of some lake in your D&D campaign. I recommend some of the same techniques used in the stories; keep the details close to the vest until the very end. Let the tension and dread build naturally by not having mythos beasties pop up like zombies in DOOM to be mowed down by the uber-capable PCs. Make sure whatever "mook monsters" they do fight are also clearly very afraid of the mysterious creature under the water, or whatever it is.

Also, changing the names and appearances slightly works well for me. My "byakhees" used a picture that I scanned from my copy of Creatures of Rokugan (and I don't think I ever actually named them) for instance.

Oh, and are you using Sanity? It just seems wrong somehow to use Cthulhu elements without Sanity playing a role in your game. Although the CoC/UA mechanics work well, I actually prefer the horror and sanity checks Mike Mearls wrote up for Darkness & Dread as a more native d20 alternative. Also, Bruce Baugh wrote up a small pdf called d20 Sanity (I think) that translates the CoC style sanity point for point into a native d20 style mechanic.

 

[Desdichado]

For that matter, saying up front that you'll be introducing Sanity and leaving it at that should probably appropriately set the stage.