Black Goo is many things. It is an organic substance as in The X-Files; a bio-synthetic or bio-technical system as in the movie Lucy; a transformative biological agent in the movie franchise Alien; a portal or gateway to Hell in the movie Event Horizon and in the commercial Fame with Lady Gaga. As an organic substance, it may be the very lifeblood or oil of planet Earth, and as a synesthetic substance may be something that contaminates that lifeblood. The contaminant is an extraterrestrial intelligence, artificial or otherwise, from space like Venom. It is legion in its control with tentacles operating on every level of society to achieve total global domination.
Beyond the metaphor it is Spectre; it is Hydra; it is the Lernean Hydra of Greek myth and represented by the very real animal hydra vulgaris; it is the Slender Man; it is the Shadow Monster or parasite; it is pure darkness and evil. It is the black technological liquid in the elixir bottle promising eternal life and delivering eternal spiritual suffering and disconnection from Source. Technologically speaking, it is programmable matter and self-assembling/maintaining micro or nano systems spread throughout the natural world to replace organics with synthetics.
It is that thing one consumes for talent, wealth, fame, etc., which only ever consumes the person making such a deal with the Devil.