The Daleks were created by writer Terry Nation and first appeared in Doctor Who in 1963, quickly becoming the show's most recognised villains. Encased in armoured travel machines, they speak with a staccato electronic voice and follow a strict belief in Dalek superiority. A line about refusing orders fits their portrayal as creatures who obey only Dalek command and reject outside authority. Clips of their voice are widely shared by fans as reaction audio, especially the dalek voice sound effect used for blunt refusals.