Gnawing Spear

You gain a +1 bonus to attack and damage rolls with this magic weapon. When you roll a 20 on an attack roll made with this spear, its head animates, grows serrated teeth, and lodges itself in the target. While the spear is lodged in the target and you are wielding the spear, the target is grappled by you. At the start of each of your turns, the spear twists and grinds, dealing 2d6 piercing damage to the grappled target. If you release the spear, it remains lodged in the target, dealing damage each round as normal, but the target is no longer grappled by you. While the spear is lodged in a target, you can't make attacks with it. A creature, including the restrained target, can take its action to remove the spear by succeeding on a DC 15 Strength check. The target takes 1d6 piercing damage when the spear is removed. You can use an action to speak the spear's command word, causing it to dislodge itself and fall into an unoccupied space within 5 feet of the target.