Control node (The Girl in the Fireplace)

The control node of Clockwork Droids operating on the SS Madame de Pompadour was the first of them to reveal itself to Madame de Pompadour.

History
The control node used a time window to enter Reinette's bedroom while she was a child and then broke a clock. (WC: Tardisode 4)

It hid under her bed until the Tenth Doctor deduced its location after stumbling on the time window through the ship, and realising it broke her bedroom clock to hide the sound of its own ticking. The droid attacked the Doctor and their struggle sent them back through the time window to the ship, where Mickey Smith found a fire extinguisher gun and doused the droid, momentarily disabling it. It thawed itself out and escaped, later trying to harvest Rose Tyler and Mickey with other droids for spare parts to rebuild the ship. The Doctor, however, returned from another venture into Reinette's time period, pretending to be drunk. The Doctor liked this particular droid, saying it was his favourite, because it was "Mr Thick Thickity Thickface from Thicktown, Thickania", and promptly poured anti-oil into its head.

Though this froze the droid's mechanical gears for a while, it recovered from the de-lubricating fluid and returned to capture Reinette once she had turned thirty-seven, thinking this made her compatible with the droids' ship of the same age. The Doctor emerged through their sealed time window on horseback and stopped the control node from taking Reinette away. He convinced all the droids to permanently turn themselves off by indicating the link back to the ship had been lost. He directly spoke to the control node, "How many ticks left in that clockwork heart, huh? A day? An hour? It's over. Accept that. I'm not winding you up." The droids deactivated, now purposeless. (TV: The Girl in the Fireplace)

Behind the scenes
The control node was listed as "Clockwork Man" in the Girl in the Fireplace credits.