Sword of Deception

You summon a pale green sword of energy and it floats 3ft off the ground that attacks any target you pick out.  It makes a melee spell attack that deals 1d8 and crits on a 19 or 20.  It deals psychic damage equal to 1d8 + Spellcasting modifier on a hit.  Any target it hits also has to succeed on a Constitution saving throw or be cursed.  A creature cursed in this way suffers a penalty to all attack, ability check and saving throws equal to 1d4, 2d4 on a critical hit.  The creature remains cursed until the curse is removed with a remove curse spell or greater restoration.
The sword attacks the same target every round at the start of your turn until you use a bonus action to tell it to attack a different target with in 40 ft.  The sword then moves 40 ft through the air and makes a melee spell attack if the target is with in 5 ft.  If the target is not with in 5 ft of it, it just floats restlessly in the air.

At higher levels: If this spell is cast with a 7th or 8th level spell slot it summons an additional sword.  If cast with a 9th level spell slot it summons a two swords for a total of 3.  When initially summoned, all additional swords always attack the same target.  You can only use your bonus action to command one of the swords to change targets, otherwise they always attack the same one.