See Spectre.
Rumour has it that spectre chose his name for the gaseous remnants of himself that remain whenever he leaves a room. These wraith-like forms emerge from glands on his skin like great diesel clouds. Leading scientists believe that these glandular secretions are protective in nature and may actually be related to pheromones. Still others believe these leading scientists are full of crap since, on occassion, it is necessary to call in a priest to exorcise the SpectreLites from their haunting ground.