Necroplasm

Necroplasm is a will-controlled magical substance featured in the fictional Spawn universe. It was originally indistinct/synonymous with psychoplasm, the substance of which Hell itself is composed. It is similar in properties, but special in that it can exist on Earth without needing to remain in one of Hell's spheres of influence as well as being allowed to traverse the mortal world without violating the non-aggression pact between Heaven and Hell. Necroplasm was a creation of the Grand-Mal Demon known as Leviathan and is exclusive to the 8th Sphere of Hell. He used it to create a demon in his own image, known as The Malebolgia (Mal), who turned on his master and usurped the 8th Sphere for his own. This gave Malebolgia full control over the necroplasmic reserves and thus the ability to create a unique army of warriors known as Hellspawn which he uses to tip the balance of power in Hell toward the 8th Sphere.