A beam of pure necrotic power blasts from your hand in a 5-foot-wide, 60-foot-line. Each creature within line must make a Constitution saving throw. On a failed save, a creature takes 8d8 necrotic damage and has its max hp reduced by the same amount. On a successful save, it takes half as much damage. Undead and constructs have advantage on this saving throw. The line disappears at the end of your turn. You can create a new line as an action on any turn until the spell ends.   The Arcanalist's say this spell has a bigger brother, but refuse to teach it.