Necromorphs are alien life-forms seen in the video game series, Dead Space. They mostly consist of human corpses that have been re-animated and violently mutated by a mutagen carried by parasitic alien life-forms.
Process of Infection
A Necromorph is created when a human corpse is attacked by a bat-like alien creature called an "Infector". The eyeless Infector will then drive it's stinger through the forehead of a corpse. The victim must be dead for the process to begin, for the mutagen it carries will simply be absorbed by a living human's immune system. There is another way to spread the infection, for suvivors that need to fullfil they starvation need, they may mistake Necromorphs' corpse for Meat, once they eat the Necromorphs fleshes, they will enter a slow and painful process and eventualy become the Necromorphs
The mutagen can infect a corpse completely in a matter of minutes or seconds. Once mutated, the affected corpse will mutate in varying ways depending on, hormonal state, age, body weight and even their rank on a ship or military.
The most common mutations usually consist of human adults. The original human arms have fused into the waist of the creature and become vestigial, replaced by two mantis-like "arms" protruding from the shoulders, terminating in long, sharp spikes. These are called "Slashers".
Another mutation is the Brute, this abomination is created by an unknown amount of corpses mutating and warping together. This creature is fast and strong. It won't hesitate to take down anyone or anything in its way.
The primary drive of the infected is to kill living humans in order for Infectors to infect their corpses with mutagen, thus spreading the mutagen. To this end, they are well equipped for the task. They can mutate into a variety of forms, getting more mutated with "age". They can survive and navigate in a zero-g environment and in the vacuum of space.
Necromorphs are extremely resilient, and are not your typical "zombie". Even when decapitated, the Necromorph will continue to attack and function. The only sure way to destroy a Necromorph is to dismember the limbs of a Necromorph, causing enough traumatic damage. The varied mutations of a necromorph require different strategies in order to defeat, but dismembering should be the basic means of destroying all forms of the creatures. However, advance Necromorphs can not be killed just by dismembering, there are some case that an advance type of Necromorphs can regenerate they lost limb, which make them impossible to kill, the only way to kill those Necromorphs it to destroy it's Body completely, such as explosion or higher form of destruction (nuke are the optimal option).