Number 10 in my quest to draw the entire 5th Edition Monster Manual: The Doppelganger!
Doppelganger is kind of a weird one, because the whole point is that it’s a monster that takes on the appearance of other people. Its true form is apparently a kind of nondescript, slightly melty purple dude. Different art depics it in different ways — the 5th Edition Monster Manual has it as a very humanoid figure. Other sou rces depict it in a stranger way, often with big “grey alien” eyes, or with an overgrown, misshapen shoulder girdle, and spikes growing out all over.