Fluidic gate

A Fluidic Gate is a type of organic structure in space used by Species 8472. These 'gates' were capable of forcing an entry into Fluidic Space and allow reinforcements in the form of heavy warships to be present. These gates were fixed structures and were incapable of movement.

''Previously, Species 8472 were known to use Quantum Singularities as entry points into their realm. So it may be that these Fluidic Gates were present on such singularities which would explain why they might be fixed though this is speculation.''

(TNG game: Armada II)