Trilanic activator

A trilanic activator was a device created and used by the Zygons to control their Skarasens. (TV: Terror of the Zygons) When activated, it sent out a signal and called the Skarasen to wherever the control was. Like most Zygon technology, the trilanic activator was biological in design. It was hand-sized and had a texture like wet skin. It would activate and could be regenerated when in an area of high diastellic transmissions.

A group of Zygons used a trilanic activator in 1909 to control their two Skarasens. The Tenth Doctor later stole it and planned to use it to put the Skarasens to sleep. It was regained by the Zygons after the Doctor's capture. (PROSE: Sting of the Zygons)

A trilanic activator activator was also used by Zygons in the 1970s. (TV: Terror of the Zygons)