A long time ago I posed this question to my friends: who would win in a fight between Cthulhu and Godzilla?
OK, it's a given that this is a nerd question par excellence, and the first person in the comments to point out that Goku with a lightsaber powered by a shard of Kryptonite would beat both of them gets a kick in the jimmy.
But seriously - I thought about it for a while and came to my decision. Surprisingly, all the friends whom I asked answered in the opposite manner.
To be brief: they posited that Cthulhu, being a terrible member of the race of Great Old Ones, is endowed with cosmic power incarnate, and would thus have no trouble dispatching a mere nuclear dinosaur such as our pal Gojira. Which is, of course, wrong.
The reason it is wrong is that the very nature of the question frames the answer. Look at it this way: if you ask who is more powerful, Superman or Batman, the answer is obvious. But ask most nerds, raised on a steady diet of Frank Miller, who would win in a fight between Superman and Batman, and most will say Batman. Because, obviously, Superman could twist Batman's head off at superspeed, shit in his neck and deposit the corpse on the dark side of the moon in the time it took Batman to sneeze, but that's not the way the DC Universe works.
Similarly, I'm not asking whether or not Cthulhu is more powerful than Gojira, I'm asking who would win in a fight. And if Cthulhu woke from his terrible slumber and decided to walk towards Japan to begin his plans for universal desolation, he'd run into Godzilla. Undoubtedly the first half hour of the movie would be spent with boring exposition - there'd be an old archeologist with a copy of the Necronomicon explaining all the bits of the Cthulhu mythos. He'd probably have a scrappy nephew or neice who was a lot more interested in reading about Gojira in the Japanese tabloids. There'd be a Gojira sighting somewhere off Tokyo Bay or something and some various other subplots, none of which would have any impact on anything.
In the second third of the movie Cthulhu would show up and start tearing shit up. He'd eat a few thousand people, make a giant throne of their bones, and just generally do everything possible to lower property values in Tokyo. If we're really going for broke, we can have the Japanese government sic Mechagodzilla on him or have Rodan (my favorite) show up to get bitchslapped. But the real fun doesn't start until Gojira shows up. They fight for a minute, Gojira gets in a fews good licks, but then Cthulhu pumps up and delivers a mighty pounding to the green guy, blasting him with cosmic energy and throwing him in the ocean or something to die. Round One goes to Cthulhu, at which point he forgets all about Gojira and goes back to summoning Nyarlathotep so he can fight Yog-Sothoth or something. There's probably a few scenes of the Japanese army getting stepped on or something to kill time in the film.
But then at about the time it looks like Cthulhu's about to destory all of civilization, that plucky young kid(s) from the first reel reappears and cries after Gojira gets beaten. Gojira is, of course, the world's biggest softy and he rises up from the ashes of his stunning defeat and brushes the proverbial dust off at this; it's on. He marches back to Tokyo and then he and Cthulhu get it on for the last twenty minutes of the film, totally demolishing the entire city. Maybe there's a couple other monsters involved, maybe not, it doesn't really matter.
But at the end of the day, there is only one possible victor: Gojira. As soon as the question became "who would win in a fight", the answer is obviously Gojira, because Gojira always wins. Cthulhu may be a being of immeasurably vast cosmic power and ancient evil, but once he steps into the ring with Gojira he's just another kaiju. He's a man in a rubber suit with an octopus head who shows up in the second reel, beats Gojira about 2/3 into the pic, and then gets defeated in a stunning turnabout. If he would just stay in R'lyeh, he would undoubtedly be able to destroy the world without much effort at all. But in choosing to step into Gojira's neighborhood, the meta-textual gods of storytelling demand that he get his ass handed to him. Because there ain't never been a guy in a rubber suit who the Big G couldn't take down if you give him 90 minutes and a plucky kids sidekick.