The Daleks are one of the most powerful races ever in "Doctor Who" history and are the Doctor's worst enemies. They cry "EX-TER-MIN-ATE!" when they are about to kill someone. They come in different colours, like bronze, black, red, white, gold, and silver. They first appeared in the first season episode of the series (in "The Daleks") and they were last seen in the Series 7 episode "Asylum of the Daleks" (2012). They are not robots, but horrible aliens kept in a metal casing, because they became mutated during a war on their planet, Skaro. They were created by an evil scientist named Davros. They can not be easily hurt by guns as their casing reflects the bullets that come from the gun and a shield melts bullets shot at them.