A cacodemon (or cacodaemon) is an evil spirit or (in the modern sense of the word) a demon. The opposite of a cacodemon is an agathodaemon or eudaemon, a good spirit or angel. The word cacodemon comes through Latin from the Ancient Greek κακοδαίμων (kakodaimōn) meaning an evil spirit, whereas daimon would be a neutral spirit in Greek and Tychodaimon would be a good spirit. In psychology, cacodemonia (or cacodemomania) is a form of insanity in which the patient believes that they are possessed by an evil spirit. The first known occurrence of the word cacodemon dates to 1398. In Shakespeare's Richard III Act 1 Scene 3.Queen Margaret calls Richard a "cacodemon" for his foul deeds and manipulations.

In popular culture

• In the popular online game, Anarchy Online, a pet that one of the professions can summon is the Cacodemon.
• In the MMORPG Talisman Online, Cacodaemons are one of the types of creature inhabiting the Cloud Mountain area.
• Deicide's second album, Legion, contains a song called "Satan Spawn, The Caco-Daemon".
• The Mega-level Digimon Daemon of the Seven Great Demon Lords is based on the Cacodemon in both name and design.