Butt-Head was the one who called her that. Sans is actually more like the Daria of the Underground, but he uses pun-based dad jokes in place of sarcasm. Still, if the Undertale cast did a Daria cosplay, Alphys would HAVE to be Daria because it's just too perfect. Her Deltarune counterpart even dresses like Daria (minus the goth boots and with a slightly different color scheme).