Tear Organs

You attempt to tear apart and horrifically rearrange the inner workings of a target creature's body. That creature must roll a constitution saving throw. On a failed save, the creature initially takes 5d10 necrotic damage. However, at the end of each of that creature's turns, it takes an additional 1d8 necrotic damage due to internal bleeding, and the horrible rearrangement that you unleashed upon its inner body. A creature that failed its save continues to suffer this damage until healed by magical means. If a creature succeeds their saving throw, they take only half of the initial damage and no additional damage on their turns afterwards.