Muto

From TARDIS Index File, the free Doctor Who reference.

The Mutos are the result of the nuclear radiation from the war between the Thals and Kaleds. They generally look like lumpy Thals or Kaleds, but the mutations can vary widely. The mutos live in the wilds of Skaro, trying to scrape out an existence in the radioactive wastelands.

Mutos were hated by both sides of the war. The Kaled mutos were driven out to maintain racial purity among the ranks. The Thals used them for slave labour, particularly for dangerous jobs. (DW: Genesis of the Daleks)