So theoretically a Yukkuri with its ass sealed shut could grow as big as say, a house, if it lived long enough to consume that much food?.....that would be a hell of a mess to clean when it finally dies...
Being sealed up like that seems like it'd cause lots of stress on the yukkuri. So while theoretically it could expand to handle the increase in size, there's not guarantee the yukkuri would survive for long.
Either it's going to give up and stop eating, freak out and throw up fatal amounts of paste, injure itself moving around (by accident or on purpose). If someone's doing this to create big eating yukkuri, the flavor's going to be bad.
Unless you spend a lot of time and effort keeping the yukkuri happy and ignoring the discomfort of not being able to take a shit. And that doesn't look like a comfortable Marisa.
The flavour wouldn't be bad... stress and discomfort improve a yukkuris taste. It's just bulging and full with filling that isn't excreted, so it wouldn't be stale. Although you could think of it that the bit that would be shitted isn't coming out, so it's being absorbed back into the yukkuri and converted back into filling as they turn anything into their respective filling. Personally, I think the only time that the yukkuri degrades or dies through eating is if the stuff is eating is really bad- i.e. poison, radioactive.
To a point with the flavor thing. stress releases sugar. Too much sugar just tastes bad. Ever try to eat a teaspoon of pure sugar?
There's two precedents for yukkuri dying after getting too full.
post #5522 These yukkuri are eating continuously until eventually they explode. Also I'd like to repeat the translation request for the two leading up to it.
post #12153 The classic ammo tale. Being bred not to crap, a reimu holds in to too long and dies.
Still not sure whether the pressure killed it, and filling leaked out of the corpse, or if it COULDN'T hold anymore and it died from a violent loss of filling. I'm thinking the former though.
OH! also, conditions in both examples are different however. The combat miko one had them eating endlessly on food they liked, which probably accounts for the greater capacity than the second, which was being forced under threat of death to eat a lot of food and not excrete.
This one's probably being fed all it can stand of food that's good for it, possibly with special attention paid to it's level of pressure.
For the ammo example, I actually think it's the latter; these Reimus are still under development.
The oversweet thing happens if something really, /really/ bad happens, at madness level I think. That explanation seems to make sense to me; the yukkuri releases way too much sugar, thus rendering it unable to think properly and driving it insane (either by corrupting the paste, or the presence of huge amounts of sugar burns it out mentally). This is definitely going to be very uncomfortable, but it's not the most terrifying or awful madness-inducing thing we've seen happen to a yukkuri. It's pretty bad but the effect would be slowly spread out over time, diminishing the effect. Varying individual differences, though.
For the ammo example, I actually think it's the latter; these Reimus are still under development. Dying from the pressure suggests that they can actually already hold their poo-poo and are dying from filling up with it, but the speech and actions ("don't do poo-poo, etc") suggest that they're struggling to actually voluntarily hold it. Narration suggests it as well- yukkuri that poo-poo are disposed of, not yukkuris that explode from the pressure.