Chicki

Chicki was an inhabitant of a human colony secretly ruled by Macra. She happened on the Second Doctor when he was trying to break Medok out of his cell. She asked if he needed help but left when he said he just dropped something. (TV: The Macra Terror)

Behind the scenes
Chicki was played by Sandra Bryant in episode 1 and by Luan Peters, under the name Karol Keyes, in episode 4.