Growing

"As the uproar reached its crescendo, the soldiers’ souls entered the open maw of the shaman. Her jaws slammed shut as she fell to the ground. Silence abruptly followed only to be replaced once again with the sound of pain. The blasphemous Growing wracked the albino’s body as souls gripped her mind. Her bones shrank and her muscles withered. She howled in pain as her paws stretched and her claws receded."

Growing is beast magic. It only works on things that have the capacity to grow (living things). It seems it can also affect human souls, assuming the human is still alive.

It works by the shaman coxing the living object to grow or otherwise change. It is easiest to work on one's own body or on a willing subject. It is hardest to work on an unwilling sentient creature, and impossible to work on anything dead. Beasts often use growing to augment their speed and strength.