Vorpon
From Tardis Wiki, the free Doctor Who reference
The Vorpon were the Guardians of the Boundary Nexus in a Grey Hole. They were an expression of the Grey Hole's intelligence. The threat that the Vorpon posed to those who intruded in the Grey Hole was to have their timeline immobilised if the threshold was crossed. Had the Vorpon's threat been carried out, the intruders would have become trapped in the Grey Hole when the Boundary Nexus was closed, although that would mean that the guardian Vorpon would also cease to exist. (COMIC: The Grey Hole)