[@ModeGone]
Yeah, Underswap!Sans is perhaps even more oblivious and adorable than regular Papyrus. He isn't actually a crybaby, and I don't intend to play him that way in the IC, so don't worry about that. The only things he'd actually cry about are:

[i]Anyone dying.[/i] Because everyone is his friend. [s]in his head.[/s]
[i]Dying himself.[/i] Even if he fought someone he'd not try to kill them even in severe situations. Anyone having the audacity to strike the blueberry down will suffer a huge post of confusion, and heartbreaking pain as he turns to dust. (And I'm not against characters dying either, so this could possibly happen at one point if something goes wrong.)

Aside from those two things, he might get emotional about back home, or just concerned about someone in the village, but those would be momentary tears for the most part. Everything else just gets reflected by his optimism, or naive nature.

Not to mention he's wasting food on feeding [b]HUNDREDS[/b] of animals that could take care of themselves. The town is going to starve.

Unless... They start eating the Pokemon.

[i]Now that's something he'd cry about.[/i]