Couple scenarios and other things I like
- An active character having their body slowly swell up over an extended period of time; as time goes on and the body gets bigger, it becomes harder for them to live out their typical lifestyle
- Non-spherical inflation; I like to see defined arms, chests, asses and thighs wherever possible
- Voice changes; e.g. a character's voice becoming [and remaining] unusually high from helium intake, or having to belch out everything they say in an unusually deep voice due to there being so much excess air in the body at once