Thalandr's Shadow Shroud

You touch a weapon. For the duration, the weapon is infused with shadow. While holding the weapon, shadows envelop the wielder's body until the spell ends, causing the wielder to become heavily obscured to others as light bends around them.

On a successful hit with the weapon, the target takes an extra 2d6 psychic damage as the shadow leap to attach to them.

At Higher Levels: When you cast this spell using a spell slot of 5th level or higher, you may choose to have the shadows leap onto an additional creature within 10ft of the target. The shadows may then leap an additional time (to a creature within 10ft of the secondary target) for every additional level above 5th.