Tenacious Blade

You create a metal dagger in your hand that is treated as a magical dagger +1. Upon striking a creature, the blade breaks off and remains stuck in the creature. The affected creature must make a Constitution saving throw at the start of each of its turns. If the saving throw fails, the creature takes 2d6 piercing damage and is incapacitated until the end of its turn. If the saving throw succeeds, the blade drops out of the wound and disappears, ending the spell.