Okay so the entirety of John Doe’s innards are black, all his organs, muscle tissue, blood, mouth, it’s all inky black (which is why when he cries it looks like he wore too much mascara to a sad movie). His pigmentation cells are even black, but they’re contracted close like an octopus does to give him canvas white flesh. When he feels threatened or highly distressed the cells open and his skin starts to ‘move’, which is actually just an illusion of the black cells opening and the white dissipating.
He has ‘gills’ up his back and a few around his waist, which is where tendrils spool out. Do not stick your hands in his gills, because if you don’t see his mouth on his face it could just sprout teeth out of the gills and bite your arm off, or pull you in.
He has six eyes and one mouth, his mouth is usually hidden.
His teeth are pink <3 As are his eyes. Those are about the only exceptions except when he blushes and his face gets REALLY RED due to the cells heating up.