Dagger of the Barbed Devil

Weapon (dagger), rare

You gain a +1 bonus to attack and damage rolls made with this magic weapon. You can use an action to cause sharp, pointed barbs to sprout from this blade. The barbs remain for 1 minute. When you hit a creature while the barbs are active, the creature must succeed on a DC 15 Dexterity saving throw or a barb breaks off into its flesh and the dagger loses its barbs. At the start of each of its turns, a creature with a barb in its flesh must make a DC 15 Constitution saving throw. On a failure, it has disadvantage on attack rolls and ability checks until the start of its next turn as it is wracked with pain. The barb remains until a creature uses its action to remove the barb, dealing 1d4 piercing damage to the barbed creature. Once you cause barbs to sprout from the dagger, you can’t do so again until the next dawn.