Teazel

Teazel was Edward Lunn's pet dog. While out hunting in September 1909, Teazel and Edward were captured by Zygons, who used their body-print technology to assume their appearances. Teazel's appearance was taken by Brelarn, warlord of the Zygons. After being rescued, Teazel guarded Edward and his family. (NSA: Sting of the Zygons)