The character who calls others "fat" is usually the villain (often named "Abusive Mother," "Mean Teacher," or "The Fat Hater"). They get their comeuppance by becoming fat themselves at the end.
While more technical, this article discusses how "varying character weights" is a fundamental tool for creators to differentiate between age groups and personality types in the software. goanimate fat
A classic back-and-forth exchange. The accused character will deny being fat, then the accuser will repeat the insult, leading to a meltdown. The character who calls others "fat" is usually