The Ifrit are a class of powerful and often rebellious Djinn (spirits below angels and devils in Arabic lore) known for their strength and cunning. Though they are most often associated with being evil, Ifrit, like all Djinn have free will and can be either good or evil. Canonically they have wings, but it seemed too complicated for Minecraft.

tl;dr: An evil Genie, who is not voiced by Robin Williams.