A weapon from the 29th century concealed inside Voyager and out of phase with normal time, which tears the ship apart with temporal fractures until Seven of Nine finds who planted it.
The temporal disruptor is a small device hidden behind a panel in a Jefferies tube aboard Voyager in the episode Relativity. It can be seen only with Seven of Nine's ocular implant, and when it activates the ship breaks up in a cascade of temporal distortions.
The crew of the 29th-century timeship Relativity, under Captain Braxton and Lieutenant Ducane, pull Seven out of time just before her death and send her back to find the saboteur. She visits Voyager in dry dock at Utopia Planitia in 2371, during a Kazon attack in 2372, and in 2375.
The culprit proves to be an older Braxton, embittered by the many times Janeway's journey has disrupted his life. Janeway herself makes the final jump to stop him.