Fulligen is an Ætherine released in excinerative reations, such as in the Core of an Ætherdrive. Fuligen is readily reabsorbed back into the ætheric medium but for the short time it manifests itself in our space it has the capacity to absorb almost all known forms of electro magnetic energy. Where the absorbed energy goes is still a mystery.
The Romlians use a special combustion method on their warships that can produce large supplies of fuligen which is used to cloak their ship from most forms of detection. Ref. Fuligen Envelopement Device. One drawback to the use of fuligen is that a ship cloaked in fuligen cannot see past the cloak and there fore must relie of using a Parascope sensor antenna from time to time. Another is that cloaked ships cannot employ any sort of navigational deflector and therefore subject to damage from Æther debris.