Greylish

 was a mutated Dalek at the centre of the Pan-Temporal Ambience. He met with the Fifth Doctor and Nyssa when they were tracking mysterious voices in the time continuum. The Greylish told the Doctor of the Daleks plan to re-invade the Earth to overwrite their previous invasion the Doctor foiled, using nano-Daleks. The Doctor made the Greylish realise that he had created this world and in return told him that he was the seed Dalek for the nano-Daleks. He destroyed his world by walking into the dimensional nullity causing the Dalek plan to fail. (AUDIO: Renaissance of the Daleks)