In an alternate reality, the time bubble was a time travel device, a vehicle that uses 30th century technology to move through time. Specific to the reality of the Legion of Super-Heroes, the time bubble was a product of the advanced engineering knowledge of Brainiac 5 of Colu.
While time traveling with fellow Legionnaires Imra Ardeen, Garth Ranzz, Rokk Krinn, Reep Daggle and Tasmia Mallor, Dox's time bubble was destroyed by a temporal distortion. The party of Legionnaires, who had been trying to return to the late 30th century, found themselves in the 23rd century of another reality where an Imperial Planets organization ruled Earth. (TOS - Legion of Super-Heroes comic: "Issue 1")