Sans chortles in appreciation. Really, his face looks no more creepy than normal from what can be seen through the sagging bandages - kind of like the skeleton is wearing a sort of ironic halloween costume.

"Excuse you, chest mimicks are a noble species." No joke, there is probably a type of monster in Sans's world that looks similar to that. "I figure we've got it made, pal. We don't gotta do a thing but wait here for the Users to make their own mistakes."

Sans is already aware of what his attack would mean for the clumsy User. He's kind of excited to see if he gets a chance to do it. He'll worry about the imminent risk of serious death later.