A creeping, wet, slithering scent, dripping with seaweed, oceanic plants and dark, unfathomable waters.
Available from Black Phoenix Alchemy Lab, the scent of Chtulhu is $15 for 5 milliliters or $25 for 10 milliliters. Link -via Simply Left Behind
Update 9/18/09 by Alex - The image on this post has been removed. It was a fan-made photoshop rendition without credit to the original artist. I've replaced it with a thumbnail of the original image of H.P. Lovecraft drawn by Bruce Timm, owned by Steven Gettis of Hey Oscar Wilde! blog - Thanks for the heads up, Steven!
Because he's one of the gods,
And not for the Deep Ones,
Who're just one step up from frogs.
http://www.zmangames.com/misc/baby_mythos.htm
I haven't smelled Cthulhu, but I had Miskatonic University which smelled like coffee, leather, and dusty old books. It was heavenly!