Mutant Phase The Mutant Phase was a dangerous mutation that the Dalek s suffered from at one point in an alternate timeline . History . During a battle , a lone Dalek was damaged by weapon fire which penetrated its casing , allowing for a parasitic wasp to enter the body . Once the Dalek returned to base , it was deemed damaged and sent to the repair bay where its genetic material was to be analysed . This was part of the Daleks ' standard practice of taking the DNA to the reproductive factories for the breeding of more Daleks . It was at this point that the Dalek Emperor from an alternate future arrived and informed them of a great catastrophe that would befall them and provided them a cure ; an insecticide that would prevent a so - called " Mutant Phase " from occurring . The Daleks distributed this cure amongst themselves and continued in their conquests . However , the pesticide cure did not work on this early stage of the mutation and the genetic elements of the wasp began to spread throughout the Dalek population . Thus began a period of deadly transformations where Daleks broke free from their casings as the Mutant Phase began to attack everything in its path . Skaro itself was assaulted and the Dalek Empire was besieged by the countless hordes of the Mutant Phase . The creatures began to spread across the universe and devastated the planet Earth . However , they mysteriously died on the planet due to the ingestion of a pesticide that affected them . This resulted in the Daleks using the technical knowledge of Professor Ptolem to provide a cure and when the Fifth Doctor arrived , the Dalek Emperor planned to use him to prevent the infection from starting in the first place by travelling back in time to the source of the Mutant Phase . Taking the pesticide cure , the Dalek Emperor , in a mind - wiped host body , approached the Daleks and informed them of the catastrophe . It was at this point that the Doctor and itself became aware that the source of the Mutant Phase was the Emperor ' s attempt at stopping them . Had he not interfered then the Daleks would have removed the alien genetic material and the Mutant Phase would never have developed . Learning the truth , this alternate reality version of the Dalek Emperor destroyed the cure , thus erasing himself and the Mutant Phase from existence . The creation of the Mutant Phase was ultimately a paradox that was centred not around the Mutant Phase but the Dalek Emperor who inadvertently aided in its creation . However , by breaking the cycle , the Emperor prevented its formation in the first place and as such the Mutant Phase did not exist in the mainstream universe . ( AUDIO : " The Mutant Phase " ) Overview . The mutation affected the Dalek mutant itself . The mutation started with a gestation period indicated by disorientation , after which the Dalek mutant broke through its own battle armour and began to grow at an accelerated rate . Its ultimate form was that of a large insectoid creature with metallic wings . These creatures were capable of absorbing energy and laying waste to entire planets in large swarms . During the transformation , the higher brain functions of the Dalek are lost and the resulting creature works through primal instincts only . This meant that they were a swarm of mindless destructive beasts that consumed whole civilisations and laid waste to the universe . While the Daleks were described as evil incarnate , the Mutant Phase was deemed as a threat that was far more dangerous . ( AUDIO : " The Mutant Phase " )