Near immobility ofc, bsausage fingers are super cute especially for cases like this where she has to grab teacups and utensils... All the other members should be like that aswell TBH

Bellies starting to get a fading red tone on the navel area from fullness... So fat you need a crane or any contraption like that to move them, any other mobility aid devices or tools just don't work anymore... This is such a mood...

The NIKKEs I kinda just did my two faves but I will turn anyone I deem inflatable into a pooltoy again someday!

Plesiosaur easily... anything aquatic is good in my book.

Any fairy will make a good balloon!
But if we're talking about blimps... of course Reisen is candidate number one, literally any type she'll make a great blimp, be it air, liquid or berry.
(sorry if this is a bit short I'm not as invested in inflation sadly as much as I like it..)

I couldn't say for certain but a good amount of characters have huge potential...
Reimu could make a great NEET, just being lazy and eating when she doesn't work, Kanako, well, mountain goddess.. need I say more..
Tewi would totally make reisen get fat and don't even realize she likes seeing her like this.
And idk what else... maybe Yuugi since oni hunger but strong fat suits her better.
In the end all Touhous should be fat methinks, let the entirety of Gensokyo waddle

YES