What interested me is that after he said 'Tankman!', he also made sure to say 'full version', implying that there are other versions of Tankman. This would mean that luffy doesn't need to eat ridiculous amounts of food every time he wants to use Tankman, and can just go straight into the 'not-so-full version' or 'hungry version' whenever he wants. Bounce man seems to be his primary offensive gear 4 form, and Tankman seems to be his defensive version, as the name suggests. Hopefully the 'hungry version' has a gimmick that makes it usable though, like he can eat almost anything while in that form and everything he eats will contribute to transforming him into full version. Idk, that's just me trying to emulate oda-logic. I just don't want Tankman full version to be a thing that can only happen when Luffy's eaten a lot, because then it would just be a one-off thing like mizu-luffy and nightmare-luffy, which would definitely suck.