In the novella Remote Control, by Nnedi Okorafor, the protagonist has the ability to emit a green radiation that is lethal to living creatures. Her power is considerable: she can kill everyone within miles, and at close range, outright incinerate several individuals.
However, at one point in the story, she is menaced by a leopard, which is able to resist her power, even approaching to within mere meters of her before falling down dead. The narration even notes that the leopard should have been turned to ash long before it could approach so close to her.
So why did she struggle so much to kill the leopard? Or alternately, why was the leopard able to resist her power for so long?