Multiple realities
(covers information from several alternate timelines)

The Fen Domar were a species encountered by the crew of the USS Voyager in an alternate timeline during their journey back to the Alpha Quadrant in the late-24th century.

In 2378, Captain Janeway's counterpart from twenty-six years in the future informed her of the Fen Domar's existence, and that Voyager would engage in a battle with them in which her favorite coffee cup would be damaged. Voyager's encounter with the Fen Domar was erased from history when Janeway's counterpart was able to return Voyager to Earth sixteen years earlier than it would have without her intervention. (VOY: "Endgame")