Chilling Scythe

You evoke a spectral scythe in your hands. If you let go of the blade, it disappears, but you can evoke it again as a Bonus Action.

As a Magic action, you can make a melee spell attack with the scythe. On a hit, the target takes Necrotic damage equal to 4d4 plus your spellcasting ability modifier and cannot regain HP until the start of your next turn. This damage bypasses any resistances. If the target is undead, it bypasses immunity to Necrotic damage.

You may also throw the scythe in a 30 foot by 5 foot line. Each creature in that line must make a Dexterity saving throw or take Necrotic damage equal to 4d4 plus your spellcasting ability modifier and cannot regain HP until the start of your next turn. This damage bypasses any resistances. If the target is undead, it bypasses immunity to Necrotic damage. You have to use a bonus action to retrieve the scythe afterwards.

Using a Higher-Level Spell Slot. The damage increases by 2d4 for each spell slot level above 2.