This idea came to me in a dream, one that was very confusing to me in a particular way because it included pony forms of my friends that aren't into fat. The basic premise is that the Everfree forest is home to a particular breed of monster.
>slimes are sentient
>slimes are fruit flavored according to their colors: red is cherry, yellow is lemon, blue is blueberry, etc.
>slimes are sanitized, no dirt or impurities are present
>a slime forcefeeding itself to a victim will take control of the victim's mana or energy reserves, regardless of race
>all mana/energy is then forced into an enchantment that greatly enhances the stretchiness of the victim's body and stomach, which allows potentially dozens of slimes to force themselves in
>slimes generally travel in packs of 12
>slimes' effects are semi-permanent: the high caloric load leads to weight gain, and the capacity enchantment leaves the victim's stomach permanently stretched (though not to nearly the same capacity) and their appetites increased to an equal or greater level
>killing a slime renders it inert, but its abilities remain present
>slimes can be baked into pies and other foods when killed
>eating slime-infused food or drinking slime-infused beverages will give a minor temporary buff to stomach capacity, and a major longer-lasting buff to appetite
As an example, eating a slice of cherry pie made with red slime will lead the pony to eating the entire pie, and to seek out more food and drink afterwards. So much as a single slime-infused cookie or slime-infused glass of flavored water makes it impossible for the pony's appetite to be sated prior to their belly being stuffed taut.