A strong metaphor requires a fitting and intelligible resemblance. Novel wording or intense exaggeration alone does not guarantee rhetorical effectiveness.
A successful borrowed image guides the hearer toward the intended significance with little strain. If the components are incompatible or the underlying relationship obscure, its force declines.
Thus “claws” suits “death” in the predator image because it concentrates the notions of seizure, harm, and difficulty of escape; an unrelated attribute would weaken the imagery.