Warp Lightning

If successfully cast, pick 1 enemy unit within range and visible to the caster. That unit suffers D3 mortal wounds.

Alternatively, before making the casting roll, you can say that this model will use its warp-power accumulator to augment the spell. If you do so, and the casting attempt is successful and not unbound, pick 1 enemy unit within range and visible to the caster. That unit suffers D6 mortal wounds. However, if the spell is not successfully cast or is unbound, this unit suffers D6 mortal wounds that cannot be negated.