- "They float in the air, belch ball-lightning, and boast one Hell of a big mouth. You're toast if you get too close to these monstrosities."
- ― Doom & Doom II manual description
Cacodemons are common demons encountered in all classic Doom games. They are also the mascot of the first classic Doom game.
- The name Cacodemon, which comes from the Greek κακοδαίμων (kakodaimon) usually meaning "evil spirit", a more precise name for what is generally known as demon (which ultimately comes from "god" or "spirit"), is in English a word that may be found in most comprehensive dictionaries.
- The monster's general visual design is similar to that of the Beholder, a similarly one-eyed classic Dungeons & Dragons monster (with eye stalks instead of horns). In addition, the Cacodemon was created from a cropping of a creature that appears on the cover of Manual of the Planes, a Dungeons & Dragons expansion book. The creature itself is known as an Astral Dreadnought, and was created by Jeff Easley for that book.
- The earliest known version of Doom to include Cacodemon graphics is the 0.5 alpha, released on May 22, 1993, and the earliest known appearance of the monster as an in-game adversary is in the press release version of Doom, released on October 4, 1993.
- Cacodemons are called pumpkins in the Doom novels, and the marine in the Doom comic refers to them as "big-mouthed floating thingies."
- Cacodemons were regularly referenced in the Star Wars franchise starting with the second issue of Star Wars Gamer on November 1, 2000 and some media after, where they are bodiless creatures from the underworld mentioned in the folklore of the galaxy and have some relation to Dark Side cults.
- Homestar Runner makes two references to Cacodemons. In Strong Bad E-Mail number 150, Strong Bad remarks that an interdimensional portal "looks like it could release some serious Cacodemons." In the Halloween 2007 cartoon, Pom Pom dresses as a Cacodemon.
- The Cacodemon is used as the Icon for the Xbox 360 Arcade version of Doom, specifically in the game library and on the Achievement screen. The sequel, Doom II, simply uses the title rather than a monster to represent the icon.
- Microsoft's Windows 95 port of Doom also uses a Cacodemon icon.
- The Cacodemon is also used as the icon for The Ultimate Doom on Steam.
- Hissy the Cacodemon (see below) serves as the Doom Wiki logo, along with a cartoonish version of the Doom logo.
- In a ZDoom-based source port, if the player is killed by a Cacodemon, one of two obituary messages will be displayed at the top of the screen depending on which attack the Cacodemon used to kill the player: "[player name] was bitten by a Cacodemon" or "[player name] was smitten by a Cacodemon" for the bite and lightning-ball attacks respectively.
- Strangely enough, Cacodemons bleed red when shot at (or green in the GBA versions), yet bleed blue when killed.
- Main article: Cacodemon (Doom RPG)
- Malwrath (gold body, red eye, red throat)
- Cacodemon (normal colors)
- Wretched (blue body, olive green eye, bright red throat)
Cacodemons attack three times consecutively and are most weak against axe attacks and plasma blasts.
"Cacodemon" or "cacodæmon" comes from Ancient Greek and means "evil spirit"; it had entered Old English by the 12th century. In ancient Greek, "demon" or "dæmon" simply meant "spirit" and was neutral; the latter spelling (usually with the ligature separated into "ae") still has neutral uses to this day.