One Piece has always aimed to mimic the stylings of Western animation classics like Tom & Jerry, Popeye, Mickey Mouse, and Looney Tunes. Characters always do wild takes, the buildings and ships squash and stretch with impacts and outbursts, people can lose their teeth and grow them back as they heal, and anyone who gorges themself on a meal can instantly burn it off. Monkey D. Luffy has always taken his world's cartoon aesthetic a step further, thanks to the rubber body his Gum-Gum Fruit granted him. Now, Luffy's Awakening has transformed him into Joy Boy and given him the power to turn the anime into a full-fledged cartoon.
Source：https://www.cbr.com/one-piece-gear-5-not-cartoony-thats-okay/
