While the Doctor is getting acquainted with another human after detecting Gallifreyan energy transformative signature in the area, the Master goes to inspect his latest victim. He walks down the toy aisle and sees the empty vial that he had given Geoffrey earlier. He shoved the blue cellophane wrapped caramel that had been Elizabeth into his outer jacket pocket.
"The Doctor had his jelly baby phase, and I may as well have a caramel phase," chuckled the Master as he examined the shelves near the vial. "Ah, yes, here we are, Geoffrey," he said lifting a ventriloquist's dummy off the shelf. It hadn't been there earlier.
If you look closely at the two and a half foot tall figure, you can see Geoffrey's features carved into the wooden head.
"Mwahahaha, Geoffrey. You were always at a loss for words and direction in your life. Now others will supply you with speech and action," the Master declared sliding his hand under the puppet's jacket and into its back.
Geoffrey's face came to life as the Master's hand gripped the controller.
"What the-?" began the words coming from Geoffrey's mouth.
The Master seated on a high stool waved his free hand's index finger at the puppet. He said, "Ah, ah, ah, no speaking on your own puppet boy. That's my job. Understand?"
The Master's lips parted but did not move. Geoffrey's voice came again from the puppet, "I understand, Master." This time his voice had the slightly unnatural cadence of a mind control victm.