Warp gate

A warp gate was a connection between dimensions or parallel universes used as a means of traveling between the two.

The Lepus Warriors attempted to invade Earth in 1923 by disguising a warp gate to their home dimension as a top hat used by the stage magician Miraclo. (COMIC: The Hat Trick)

Death's Head was mysteriously transported to the "robot universe" through a warp gate. The Seventh Doctor later admitted he was the person who had done so. (COMIC: The Incomplete Death's Head)

Behind the scenes

 * In NOTVALID: Scream of the Shalka, the Shalka use a warp gate, also known as a space-time tunnel to invade Earth from their homeworld.