Peg doll (Night Terrors)

The Giant Peg Dolls were life-sized dolls that inhabited the doll's house in George's cupboard. (DW: Night Terrors)

Powers and abilities
The Peg Dolls turned their victims into other Peg Dolls. The transformation was swift. It began with the hands, which grew bigger and turned to wood, followed by the rest of the victim's body. None of the person's original personality remained; the Doctor referred to it as a state of 'living death'. It was possible to reverse the process, although the victim apparently retained no memory of the ordeal. (DW: Night Terrors)

History
The Peg Dolls inhabited the doll's house in George's cupboard, which became a psychic repository for all his fears. Subsequently, the dolls were animated, and began hunting any individuals who appeared in the house to turn them into Dolls.

When Rory and Amy were trapped in the house, they stumbled across the dolls and believed they were harmless. Eventually they realised the extent of their powers when they witnessed Purcell being turned into one of them, and tried evading them as much as possible. They also began hunting the Doctor and Alex when they appeared in the doll house, until they managed to corner them and Rory, having managed to convert Amy in the meantime. They proceeded to attack them, momentarily stopping when George himself appeared in the same room.

The Dolls turned their attention to George and surrounded him, until Alex pushed them aside to comfort his son and assure him that he would never abandon him. When Alex's unconditional love for his son allowed George to overcome his fears, the Peg Dolls were expelled from the house and reverted to their original form. (DW: Night Terrors)