The Empty Child, The Plague, Gas Mask Zombie, whatever you wanted to call it, you wanted it to stay AWAY. When a group of nanogenes from a Chula ambulance crash land to earth by mistake (courtesy of Jack Harkness), the first person they find to heal is a little boy named Jamie who was wearing a gas mask (during WWII). The nanogenes, having never encountering a human before, assumed that the gas mask, injuries, zombie like actions and cries for mom said by a dying boy were totally normal and started applying those same characteristics to anyone else in the area who got hurt and needed help. Even more horrifying, the Chula nanogenes gave the little boy and the other town residents super strength and telepathic powers. On a constant search for his mother, Jamie wandered around until he found her. When the nanogenes figured out that his mom was a way better human template to go for, they realized their error and put everyone back right, even to the point of growing back whole limbs for people (much to their confusion).

The Chula nanogenes and the Empty Child were seen in The Empty Child and The Doctor Dances. References to Jamie’s cries of “Are you my Mummy?” have also been referenced in other episodes as a running gag in The Poison Sky, and Mummy on the Orient Express.