Mancubus (Doom 3)

The Mancubus is one of the few Doom 3 monsters that remains faithful to its original design. Like the original version, the Mancubus is a very large, fat demon with a fireball launcher for each arm, but unlike the original, it does not fire the two launchers simultaneously, firing each in turn instead. The Mancubus stands about 7 feet tall, and its bulk is about 2 to 3 times as wide as a normal human. It is greenish-grey in colour, rather than brown like the classic Doom version.

Compared to the original design, the Doom 3 mancubus is more elephant-seal- or Cthulhu-like (the Making of Doom 3 book points out the latter as a source of inspiration). The strange head was explained by the game designers: the centre tentacle is a breathing tube, consisting of tiny holes along its sides (which are visible if viewed closely), while both side tentacles were actually supposed to be tusks. Due to a graphical and model design glitch they were reduced to feeding tools, and are stated to be used like the mouth of an octopus. It is unknown whether they have a beak inside their mouth or not. In Doom II, the Mancubus had a mouth, leather-colored skin, and elephant-like feet. In Doom 3, the Mancubus has a small "trunk" instead of a face, pale skin, and their feet look like fanned out pieces of flesh at the end of amputated legs.

Mancubuses are quite rare, and only appear in two levels of Doom 3. They first appear in a sort of "mini-boss" fight against 3 Mancubuses in Recycling Sector 2 (possibly mirroring the Mancubus's introduction in Doom II's seventh level), and several are also encountered throughout Hell. They also appear in Resurrection of Evil and The Lost Mission, although again they are mostly confined to Hell.

Combat characteristics
The Doom 3 Mancubus has extremely high offensive capabilities. Though it can only fire one cannon at a time unlike its classic counterpart, it more than makes up for this by being able to fire a steady barrage of powerful fireballs from each cannon, unlike the classic version's series of three volleys. It is also tougher than the classic version, taking 2 to 3 magazines of Machine Gun fire, a full magazine of Chaingun or Plasma Gun fire, or as many as six direct rocket hits to kill, making it the toughest (but also one of the slowest) non-boss creature in the game.

The Doom 3 Mancubus also has a melee attack: both of its cannons can be used as hammers, which it rears high up into the air to bring smashing back down. It is possible to use the long recovery time from this attack to kill the Mancubus with melee attacks (chainsaw being the best bet). However, melee combat is an extreme risk, as the Mancubus's crushing melee smash is the most powerful enemy melee attacks in the game, save only the Cyberdemon's instant-death stomp.

Tactical analysis
Mancubuses are real powerhouses, with the highest health for a non-boss creature, and a powerful ranged attack with a reasonably high rate of fire. Players are fully justified in using their most high-powered weaponry to bring one down. The weapons that are most effective against the Mancubus are the Chaingun, the Rocket launcher, Plasma Gun, and the BFG. Grenades also work well due to the lumbering speed of these behemoths. Headshots are effective and quite easy to score on a Mancubus, since they are a slow moving and very large target. A Mancubus can be killed with about 4 rocket launcher headshots. If the Soul Cube or Artifact is available, by all means use it.

Trivia

 * If the Mancubus model is examined more closely (e.g. using the noclip cheat or a model viewer) it is possible to see hooks with suckers where the trunk begins, suggesting the trunks are actually feeding tools; when the Mancubus shakes its head, they flap around. This is a visible indication that the design of the Mancubus was inspired by Cthulhu, like many elements of Quake. The tentacles can be seen prominently in the beast's introduction cutscene.
 * If one looks closely, nipples can be seen on the Mancubus.
 * The Vagary's transparent abdomen contains a malformed Mancubus fetus, leading to fan speculation that the Vagary is the "mother" of the Mancubus species. There is no confirmation of a relationship in the game itself, however.
 * These monsters are usually accompanied by Cherubs in the original and in the expansion. This has lead to similar speculation that they could be offspring of the Mancubus.