Without really thinking about it, mostly since Frisk is close enough to do so, Sans-Serif reaches out to try and hold their hand as they walk. He doesn't look all that encouraged as Frisk explains what cats eat, especially since he finds himself agreeing with their assessment that Duchess doesn't look like a hunter at all. Even he can see that much. She's clearly used to having people feed her.

He can relate.

But not all is quite so hopeless. His eyelights glow a bit brighter with a sudden rush of enthusiasm.

"oh! i know where the milk is! i drink it all the time." Sans doesn't have access to everything he'd need in order to make the two experiments less fragile, but he's been making do where he can.