The Varnų Karalienė's Visage

You evoke a shadowy visage that appears above you. The visage remains until you use your action to make a melee weapon attack against a target within range. On a successful attack, your attack's replaced by the visage's, who hits your target with a necrotic scythe, dealing 4d6 necrotic damage and forcing the target to pass a Dexterity save or have its movement speed reduced to 0 until the end of their next turn. The visage then disappears.

At Higher Levels. When you cast this spell using a slot of 3rd or higher, the damage increases by 1d6 for every slot above 2nd.