Claw of the Rakshasa

Make a melee spell attack against a creature. On hit, the target takes 2d6 + your spell casting modifier Slashing damage and is cursed. The magical curse takes effect whenever the target takes a short or long rest, filling the target's thoughts with horrible images and dreams. The cursed target gains no benefit from finishing a short or long rest. The curse lasts until it is lifted by a Remove Curse spell or similar magic

When you cast this spell with a 4th level spell slot or higher, the Slashing damage done by this spell increases by 1d6 for every spell slot above 3rd level.