Godzilla vs. Cthulhu
I loves me some Godzilla. I REALLY loves me some Cthulhu. So like chocolate and peanut butter, putting them together seems like an awesome combination.
AND IT IS!
I had no idea there was so much fan work of this type, but there are indeed GvC fans out there. There's even a whole story on fanfiction.net. I will warn you, the links above exceed your daily allowable dose for awesome.