The Master's Creepy Auton Doll

This small Auton was used by the Master as a means of assassinating his enemies. He would slip the doll into their bags or cars and it would then awaken when near heat and attack anyone in the vicinity. The creepy little thing was used by the Master to great extent during his alliance with the Autons, and it killed many people. It even tried to kill the Doctor but it was soon shot to bits by one of his UNIT friends.