A high potent, and highly dangerous fuel. It appears naturally only by being harvested from a black hole. It is considered by many to be the most potent form of liquid fuel.
It is usually a bright yellow liquid or gas.
Nucleon is a cross between Engen/Energon and Super Dense Matter. It is probably the heaviest fuel in the known galaxy, and also the most potent. A kilogram of this stuff is said to be able to 'push a world into hyperspace'. While hyperbole, the substance is incredibly powerful, perhaps too powerful. It is dangerous for most mechanical systems, causing a variety of malfunctions at random. In mechanical life forms, the end result is usually a dramatic increase in power, but with random mutation/malfunction. For beings like TechnoMorphs and Vandoricons, and Transformers, the result is an increase in power, life force, but a loss of their transformation ability.