This bone rod is carved into the shape of twisting tendrils or tentacles. You can use this rod as an arcane focus. The rod has 3 charges and regains all expended charges daily at dawn. When you cast a spell that requires an attack roll and that deals damage while holding this rod, you can expend 1 of its charges as part of the casting to enhance that spell. If the attack hits, the spell also releases tendrils that bind the target, grappling it for 1 minute. At the start of each of your turns, the grappled target takes 1d6 damage of the same type dealt by the spell. At the end of each of its turns, the grappled target can make a Dexterity saving throw against your spell save DC, freeing itself from the tendrils on a success. The rod's magic can grapple only one target at a time. If you use the rod to grapple another target, the effect on the previous target ends.