How would win in a battle between a Giant Tiranosaurius Rex and Godzilla?
Godzilla. Canonically Godzilla's atomic breath is capable of killing most kaiju (giant monsters) in one hit. Assuming the T-Rex is about the same size as Godzilla, it would only have its bite and tail to attack Godzilla with. His hide is known to be more or less immune to e.g. tank shells, so it is unlikely that the T-Rex's teeth would be able to damage him. Ultimately, Godzilla would probably destroy the T-Rex quite quickly.