I didn't put anything in the chocolate. [Which, wow, only makes it sound like he absolutely did, huh? But in this case the chocolate was sealed in plastic when Papyrus got it, so there's some evidence to prove Sans isn't lying.] I woke up, hung out with you for a bit, took a nap [with his window open, to better soak up sunlight, though it doesn't occur to Sans to list it--but that's when the pollen got in], figured I'd make that maze when I woke up, so I skipped work and did that. Watched TV for a while. Then you got back. [The maze took up most of his day. He did stop for food a few times, but it was food he ate, not food he gave to Papyrus, so...] I've just been here today.

[Is their house infected with something?]