Vein Burst

You attempt to burst a vein in a creature you can see within range. The target must make a Constitution saving throw or take 3d6 necrotic damage on a failed saving throw. Until the spell ends, you can use a Bonus Action on each of your subsequent turns to cause this damage again. The creature can make an additional saving throw at the end of their turns to end this effect.

At Higher Levels. When you cast this spell using 4 or more hit dice, you can target one additional creature for each additional hit die Spent.