I lifted a hand but he sharply held his right palm out to me. I took this to be an arresting gesture, but I simply had to know. I slowly moved my raised hand rightward, then quickly tapped him on the shoulder with my left. His mimicry lasted only until a half-second after that, as lightning spiderwebbed up his neck and over his face. I spun around in reflex to a sound like that of breaking glass, and when I turned back, all that were left of my doppelganger were a pile of clothes and a scroll with characters scrawled in what looked like blood.