WTF? That's a fair question when the internet throws out a term like "unicorn skin." When stylist Samantha McMillen shared a snap of a glittering pair of Louboutin boots that change from silver to rainbow sequins with a quick swipe, she captioned the 'gram, "I'm calling this 'Unicorn skin.'" Well played, Samantha. We don't know what else we'd call the magical, mystical effect - but we'll happily take them for a test drive. In fact, we'll skip the Frapps, makeup, and hair dye if we can just rock these unicorn heels.