Mastering v cartoon drawing involves lots of observation. Notice how light and shadow fall on objects in real life. And don't be afraid to make mistakes - they're part of the learning process. Also, joining drawing communities can give you valuable feedback and inspiration.
A stubborn man in cartoons often refuses to change his mind easily, even when faced with obvious evidence. He might insist on his own way despite others' advice.
The Silver Age, around the 1950s to 1970s, brought more complex plots and diverse characters. It saw the reintroduction of popular heroes and the rise of Marvel Comics.
In my opinion, Hulk might have the upper hand. His raw power is just too overwhelming for Luffy. However, Luffy's agility and creativity in using his powers could give him a chance to outsmart Hulk.
Superman parody comics typically have elements like making fun of his superhuman abilities, changing the storylines in a wacky way, or giving him a completely different personality for comedic effect.