Several Disney villains that poses Caucasian features are given unnatural and impossible skin tons in several Disney films. Notable examples of this include Ursula’s purple skin in The Little Mermaid, Maleficent’s green skin in Sleeping Beauty, Hades’s blue skin in Hercules, and Yzma’s grayish-purple skin in Emperor’s New Groove. Many other Disney villains have skin that is whiter than the protagonists and borders on gray.
Why Disney decided on these choices might including several reasons. For example, giving a villain a strange skin tone makes them an “other” marking them as an enemy to the protagonist. It also designates villains as being another race without having to portray an actual race. No one will be offended if Maleficent has green skin, but red skin (Native Americans) and yellow skin (Asians) are entirely off-limits.
This difference is especially startling in the Emperor’s New Groove in which the Incan people are all tan and Yzma stands out entirely with her strangely pale and purple skin. The difference, as in all of the Disney films with colored villains, is never explained.
It is also fairly regular for the Caucasian villains and villainesses to have skin so white that it takes on a grayish hue. The clearest example of this is Cruella DeVille from 101 Dalmatians. In this still from the film below, she is clearly a different, more unnatural (and eerily corpse-like) shade than Roger, the male protagonist.
Once again, Disney portrays the villains and villainesses as being outside of the norm by differentiating them by skin color.