Mancubus

Mancubi are enormously bloated, cumbersome but tough demons that look somewhat like extremely overweight humans. They do have some distinct demon features though - all green eyes, deformed feet, pointy teeth and three pairs of nipples. In addition their arms have been replaced by huge, rapid-firing fireball cannons powered by a generator strapped onto their backs. The game manual describes the Mancubus as follows:
 * The only good thing about fatso is that he's a nice wide target. Good thing, because it takes a lot of hits to puncture him. He pumps out fireballs like there was no tomorrow.

The plural of Mancubus is "Mancubi" rather than "Mancubuses": this is according to John Romero, who was asked as to the correct plural form. This follows from the latin pluralisation of the word, as "mancubus" comes from "succubus", plural "succubi".

In the Doom novels, they are unchanged. They have so much fat and so many skin rolls, however, that their eyes and ears are almost completely covered, leaving them nearly deaf and with poor eyesight. They are also believed to be an early attempt to grow genetic human copies.

Strategy
Mancubi are dangerous opponents, but have a number of exploitable weaknesses. They are slow, and make large targets, so are easy to kill with rapid-fire weapons. Furthermore, because they pause briefly before attacking, it is pretty easy to prevent them from attacking using slower weapons, even the super shotgun. When they do attack, it is helpful to attempt to keep one's distance. Otherwise, the player might take two fireballs instead of just one. When dodging from a greater distance, it is important to avoid overdodging. With the first two attacks from the Mancubus, one fireball will go straight toward the player while the other two will fly off to the left or right. In the third volley, one will go left and one right. This pattern can be figured out and used to avoid Mancubus attacks.

Doom RPG
In Doom RPG, the Mancubus appears as a class of monsters. There are three variations, identified by color:


 * Blue : Behemoth
 * (Normal colors) : Mancubus
 * Red : Druj

Doom 64
While their function is unchanged, their appearance is greatly altered. They have less fat and a more bear-like face, are taller and wear a metal body harness.

Appearance statistics
The IWADs contain the following numbers of Mancubi: