Clockwork Droid
The Clockwork Androids are the villains of the Tenth Doctor episode The Girl in the Fireplace. They are sent by an unknown person to stalk and destroy Madame de Pompadour in 15th Century France.
Their robotic faces are hidden by terrifying masks that are twisted into a grin, making them look like someone from a masquerade. Their gloved hands hide sharp saws, so they can take human body parts. Whenever they are in the room, they make a scary 'tick tock' noise. Their appearance may have something to do with the broken clock on Madame de Pompadour's mantle-piece. They have many different names: The Elegant Androids, the Clockwork Robots, clockwork killers.