[For a moment, Sans looks at the man. Really looks at him. Surrounded by humans as Sans has been for some time now, it was only natural to notice consistencies. The subtle shift of veins under skin, the imperfections, the protrusions of bone, the stretch of sinew when extending an arm. These things were normal for humans, as far as Sans could tell.

There was something abnormal about this human.

He says nothing about that, of course. Observer effect was a bitch, and Sans would rather avoid it.]

Got it in one, pal. A power converter, actually. It takes geothermal energy generated by subterranean magma and filters it into magical energy. Took us out of the dark ages... y'know, literally.

[Besides... he was enjoying himself too.]