Moebius

A moebius is a hypothetical twist in the fabric of space, wherein time becomes a loop from which there is no escape.

In 2365, after the crew of the USS Enterprise (NCC-1701-D) encountered Captain Picard's counterpart from six hours in the future, Lieutenant Worf suggested that a moebius may have been responsible, although an exotic energy vortex was ultimately determined to be the cause.