Befuddling Blade

You brandish the weapon used in the spell’s casting and make a melee attack with it against one creature within 5 feet of you. On a hit, the target suffers the weapon attack’s normal effects plus psychic damage equal to your spellcasting ability modifier and then becomes infected with lingering psychic energy until the start of your next turn. If the target willingly attacks before then, the target subtracts 1d4 from their first attack roll, and the spell ends.

This spell’s effect increases when you reach certain levels. At 5th level, the attack roll penalty becomes 1d6. The penalty becomes a 1d8 at 11th level and then a 1d10 at 17th level.