Wendigo
In Algonquian folklore, the wendigo () or windigo is a mythical man-eating monster or evil spirit native to the northern forests of the Atlantic Coast and Great Lakes Region of the United States and Canada. The wendigo may appear as a monster with some characteristics of a human or as a spirit who has possessed a human being and made them become monstrous. It is historically associated with murder, insatiable greed, and the cultural taboos against such behaviours.
Indigo
However, the correspondence of this definition with colors of actual indigo dyes is disputed. Optical scientists Hardy and Perrin list indigo as between 445 and 464 nm wavelength, which occupies a spectrum segment from roughly the color wheel (RGB) blue extending to the long-wave side, towards azure.