Necrotic Burst

This weapon deals an additional 1d6 negative damage on hit. In addition to the extra damage, a necrotic burst weapon deals an extra 1d10 points of negative energy damage on a successful critical hit. If the weapon's critical multiplier is ×3, add an extra 2d10 points of negative energy damage instead, and if the multiplier is ×4, add an extra 3d10 points of negative energy damage.