Viola's Blood Curse: Wither Blade

You summon a blade made of necromantic energy and blood that forms around a weapon that comes into contact with a drop of your blood. On a hit, the target suffers 2d8 necrotic damage.

The target must make a Constitution saving throw or become inflicted with a blood curse on a failed save, and not be inflicted on a successful save. Upon being cursed, the creature takes 1d8 necrotic damage at the end of each of its turns. This curse lasts until the spell ends or is dispelled.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d8 for each spell slot above 2nd.