Weeping Angel Museum Phone Case

According to the Doctor, the Weeping Angels "are as old as the universe (or very nearly), but no one really knows where they come from." He also describes them as "the deadliest, most powerful, most malevolent life-form evolution has ever produced." Weeping Angels are unusual as predators in that they neither kill nor directly parasitize their prey. Their usual mode of feeding is to make use of time paradoxes - with a single touch, a Weeping Angel can send a person into the past to a point before his/her own birth, and can then feed off the "potential energy" of the years which that victim would have lived in the present. The Doctor describes the Angels as "the only psychopaths in the universe to kill you nicely".