As for Cthulhu's size, if you take Lovecraft’s description literally, It had to squeeze through a doorway an acre across.
Briden pushed at the stone in several places without result. Then Donovan felt over it delicately around the edge, pressing each point separately as he went. He climbed interminably along the grotesque stone moulding - that is, one would call it climbing if the thing was not after all horizontal - and the men wondered how any door in the universe could be so vast. Then, very softly and slowly, the acre-great lintel began to give inward at the top...
