Thalek (Auld Mortality's universe)

In a parallel universe, the Thaleks were a race that conquered half of Mutter's Spiral. Their war cry was "Annihilate!".

The Doctor was worried about their actions and the fact that the Time Lords did nothing to stop them. He later encountered them during his travels, after he left Gallifrey. (AUDIO: Auld Mortality)

The Doctor and Susan once brought a group of Thaleks to Trafalgar Square. The Thaleks wanted to feed some pigeons. (PROSE: The Innocents)

Behind the scenes
The Thaleks were created as an Unbound counterpart for the Daleks. Both races were warrior races, had a similar battle cry and were seen as a threat for the universe by the Doctor. As the name is a portmanteau of the Daleks' name and that of their ancestral enemies the Thals, the implication is that in the absence of a wandering Doctor, it was not the Kaleds but rather the Thals who developed into Dalek-like creatures.