Mettaton's taken aback at the quiet question, and pulls away to raise an eyebrow at Napstablook. Surely...they have more faith in him than that?!

Then he realizes with an uncomfortable pang of guilt that he hadn't really given them much reason to as of yet. Along with that guilt comes a rush of heat to his face, which he immediately attempts to cover with one gloved hand.

He does so sorely wish that he could control that particular function.

"No, no!!! Of course not, I came here to pick you up, Blooky dear! You're coming with me, I just--I missed you, and it's a little selfish, is it not? To want you here where you are corporeal and you never wanted that?"

Hey. At least he's trying to be sensitive, even if he can't quite empathize with wanting to stay a ghost.