Warhammer: Unofficial 9th Edition

Warpstone Mutants

As a result of the many near-catastrophic accidents that have occurred during the development of the Klawmunkast's Rat Tank, a number of his slaves (basically those who survived the explosions and warpfire leaks) have mutated into grim parodies of Skaven. Although they have lost their minds, these degenerated ratmen have developed extra limbs or had their musculature increased making them much stronger.

If Klawmunkast is included in your army, you may upgrade one unit of Skavenslaves to Warpstone Mutants for +2 points per model. Warpstone Mutants have +1 Strength and Attacks.