A being of electromagnetic energy native to a Class J nebula which, in the tale Neelix tells the Borg children, became trapped aboard Voyager and took over the ship.
The electromagnetic lifeform is a non-corporeal being that lives inside a Class J nebula and cannot survive for long outside one. Once aboard a starship it spreads through the systems and can control them, speaking by stitching together phrases from the computer's voice.
It appears in the Voyager episode The Haunting of Deck Twelve, set in 2376, as the subject of a story Neelix tells Icheb, Mezoti, Azan and Rebi during a power shutdown. In his account, Voyager destabilised the nebula while gathering deuterium and the creature was swept aboard.
As its temporary environment failed, it grew frightened and violent, gassing sections and injuring crew. Janeway finally persuaded it that she would find it a new home. The shutdown that frames the story is the ship releasing it into another nebula.