Anerythristic (anerythristic A, Sometimes called black albino) The inherited recessive mutation of lacking erythrin (red, yellow, and orange) pigments produces a snake that is mostly black or gray.

Melanism (also known as melanosis; from Greek μελανός, "dark-colored") is the occurrence of an increased amount of dark pigmentation (as of skin, feathers, eyes or hair) in an organism, resulting from the presence of melanin. It is the opposite of leucism and albinism, which occur because of a lack of melanin or other types of pigment.