Curse of Blades

Unholy bands of black energy tie a creature to its weapon. Choose a creature you can see that is holding a weapon within range to make a Wisdom saving throw. On a failed save, the creature is cursed for the duration. A cursed target can't willingly drop or stow its weapon. Additionally, whenever it takes the Attack action on its turn, it makes one additional attack using its weapon targeting itself, against  its own AC, dealing damage as normal on a hit.  

A remove curse spell ends this curse early.