Melody Pond (The Impossible Astronaut)
This girl contacted Richard Nixon for assistance, but he did not know who was calling him. She told him about the "Monsters", and how she feared them.
The girl told Nixon the words "Jefferson Adams Hamilton", leading Nixon to believe she was a boy, but the Eleventh Doctor helped them to discover that these were the names of street names, the only three in the same place together in Florida, and probably all of America, according street names and the only place these were together was Florida. She watched from a distance when the Doctor arrived to find her.
The girl eventually approached the Doctor and Amy Pond, with the latter firing a gun at her. (DW: The Impossible Astronaut)
Three months later she again encountered Amy, who had only shot a hole in the suit's visor, in what appeared to be her bedroom at the Graystark Hall children's home. The room was full of photos of the girl, and one of Amy holding an infant. The Silence then appeared in the room behind the girl and took Amy hostage.
The girl was able to free herself from the suit, which had been fitted with alien technology to act as a life support system. In order to break free she displayed enormous strength, ripping the suit open. She then ran from the scene after spying on the Doctor, Canton, River and Rory rushing to help Amy.
Six months later, her deteriorating health caused her to regenerate in a New York alleyway. (DW: Day of the Moon)
