
The Mancubus (plural: Mancubi) is a type of demon from the DOOM video game series. Introduced in DOOM II, it is a cybernetically enhanced humanoid creature with a large, bulbous body. It is among the strongest demons encountered throughout the series, capable of soaking up large amounts of damage while dishing it out in equal measure.
DOOM II[]
In its first appearance, the Mancubus appears as a large, fat humanoid with flabby brown skin that slowly walks on stumpy legs which sport three toe-claws. Its forearms have been replaced with cybernetic cannons that continuously pump out fireballs, delivering massive damage to the player. A pair of fuel tanks are grafted onto the monster's back.
Mancubi take a considerable amount of firepower to kill. Chaingun fire can whittle their health down quite quickly, though the Rocket Launcher is perhaps the most effective weapon against these beasts.
DOOM 64[]

The Mancubi of DOOM 64 were created from the resurrected carcasses of demons that perished during their first attack on Mars. Resurrected by the power of the Mother Demon, these creatures are more ferocious and powerful than before. They have undergone a certain degree of mutation during the reanimation process, becoming more muscular and developing longer legs for a marginal increase in speed. They are also outfitted with metallic harnesses that grant them greater protection from the Doomguy's arsenal.
This version of the Mancubus is armed with similar weapons to its DOOM II predecessor, though its fireballs are fired at an increased rate and are smaller. With their resilience, higher-grade weapons such as the Rocket Launcher, BFG or Unmaker will be needed to bring them down.
DOOM 3[]

Unlike most of the creatures in DOOM 3, the Mancubus' design has only undergone minor alterations and still closely resembles its original design. Its large body consists of deathly pale skin and is supported by a pair of tree trunk-like legs with stubby clawed digits. Instead of a proper mouth, the creature's head sports a pair of tentacle-like mandibles with a black tube running between them. The tube runs from the monster's face and into its chest, acting as part of a respiratory system.
As with previous iterations, the Mancubus has a fireball cannon grafted onto each arm. While it is only shown to fire one cannon at a time in DOOM 3, it has a higher rate of fire than in previous games. It also has a powerful melee attack, slamming its arms down like hammers upon the player if they dare to get too close. As the toughest non-boss enemy in the game, the Mancubus can be quite difficult to kill. It can take three full Machine Gun magazines to kill this monster, otherwise an entire Plasma Rifle or Chaingun clip, or six direct rocket hits.
DOOM (2016)[]

The Mancubus has undergone a significant redesign for DOOM (2016). Not only is it larger than ever, but most of its body is now adorned with metallic armour that covers the shoulders, chest and legs. Its head sports a single green eye and a gruesome mouth filled with jagged, rotten fangs. Its belly remains unarmoured and is grossly distended, providing an obvious vulnerable spot.
According to the report files of Dr. Olivia Pierce, the Mancubus will feed on just about anything, even decaying flesh. That which they consume festers in their putrid innards and produces highly flammable toxins which are routed into the cannons on their arms, providing them fuel. It can launch globs of this corrosive substance at great range or otherwise use it to fuel their flamethrower attacks. If prey get too close, the Mancubus can unleash a deadly wave of Argent energy and destroy them instantly.
While undeniably powerful, the Mancubus is slow and relatively easy to dodge. Its belly also provides an inviting target and can be ruptured with enough firepower. It is possible to kill a Mancubus with a single well-placed shot from the Gauss Cannon. Upon death, the creature's belly bursts and saturates the area around it with its toxic ichor.
DOOM Eternal[]

In DOOM Eternal, the Mancubus' design has been altered so that it more closely resembles its original design from DOOM II; a bulky humanoid form with pinkish skin, two green eyes, stubby legs and a cannon grafted onto each arm. It also sports a cybernetic implant on its chest which can be exploited as a weakness.
This version of the Mancubus behaves in a similar style to its 2016 counterpart. It lumbers about slowly, launching fireballs in the Doom Slayer's direction, switching to flamethrowers at mid-range and generating puddles of napalm at close range. Unlike previous variants, this version of the Mancubus has multiple weak points to exploit, such as the implant on its chest. Striking the chest will deal additional damage and can also be attacked for a Glory Kill. During combat, the player can target the Mancubus' arm cannons and destroy them, eliminating its flamethrower attack and making its regular fireballs weaker.