Originally Posted by
The Dog
I seem to remember Luffy having pretty shit heat/flame resistance feats, since he's made of rubber and One Piece tends to go with "rubber is an insulator so any amount of lightning can't effect it, but heat melts rubber so heat/flame messes him up". And Godzilla's ambient field was turning steel to liquid seemingly near-instantly just by being inside it, so it had to be extremely hot. And the active bursts basically atomized Ghidorah faster than Monster Zero could regenerate, and Ghidorah was regrowing a lost head in a few minutes.
Of course, Whitebeard survived for a while and kept fighting after getting a fist of magma in the chest (anime) having half his head burned off (manga), so who knows.