She spoke his language. In fact, his eye sockets practically sparkle with enthusiasm as she mentions dimension hopping. "YES!!!" He shouts, without realizing how loud he's shouting, because it's Papyrus and this is pretty normal for him. But oh, this is great. Fantastic. Terrific!

He chuckles and brings a hand over his chest. "I'm of the opinion that some sort of dimensional vortex must have opened up. Perhaps a tear in the space time continuum? I've actually dabbled with inter-dimensional travel myself! A little. BUT! I think the real question we should be asking is what sparked this particular rift. Or vacuum."

Tapping his foot, he proceeds to stroke his chin. "Hmmm... perhaps the source is a fellow genius like ourselves, who sought companionship from across the multiverse! So they built a big, memory portal device."

Or maybe he's projecting slightly.