Trilanic activator

A trilanic activator is a device created and used by the Zygons to control their Skarasens. When activated, it sends out a signal that says "eat me, eat me" and calls the Skarasen to wherever the control is.

The group of Zygons used a trilanic activator in 1909 to control their two Skarasens, one which was killed by the other through the use of the activator. (DW: Sting of the Zygons)