Type 4 quantum singularity

From Memory Alpha, the free Star Trek reference

A type-4 quantum singularity is a spatial distortion which emanates from a highly localized disturbance in the space-time continuum with a gravimetric flux density of over 2,000%. Type-4 quantum singularities output massive subspace interference preventing the use of tractor beams.

In 2371, the USS Voyager, while traveling in the Delta Quadrant, became trapped in a type-4 singularity. (VOY: "Parallax")