Hmm. No, it's... it's not normal. Not for anybody, even him... He hasn't done that stuff in years, I think.

[It's tricky to say for sure, with all the time Sans was in the carnival. But it doesn't seem likely Sans had been thinking enough to do that mysterious science stuff, with how on edge he'd been when Papyrus arrived.]

...But, I've been wanting to make things I've never tried making before. It could be more of the same. I don't know! How else was he weird?