Original: In Egyptian mythology, Apep (also spelled Apepi, and Aapep, or Apophis in Greek) was an evil demon, the deification of darkness and chaos (isfet in Egyptian), and thus opponent of light and Ma'at (order/truth), whose existence was believed from the Middle Kingdom onwards.
Simplified: Apep (also spelled Apepi, and Aapep, or Apophis in Greek) in Egyptian mythology was an evil demon.