The good doctor nearly forgets to continue twirling his weapon at the sight he has just beheld. What kind of magic was THAT?! He's never seen anything like it before: Miss Muffet's magic directly interacted with Not-Asgore's astral projected state! Remarkable!

"-good golly! What did you just - that was - but then...?!"

...it's quite rare he's at a complete loss for words. It's suddenly proving extremely difficult to keep his guard up when his mind is overrun with confusion, inquisitiveness and some good old-fashioned academic excitement. These creatures can not only cast astral projection at will, but have entire abilities revolving around it?! This is a discovery that could rival the original discovery of magic outright!

"How did you do that? How is he doing that? How are the both of you-"

Faust realises too late he has, in fact, dropped his guard entirely in favour of gesticulating as he speaks. Duck and cover!