Sectumsempra

Make a ranged spell attack against a target within range. On a hit, the target must make a Constitution saving throw. On a failed save, a creature takes 10d6 slashing damage and another 5d6 slashing damage at the end of its next turn. On a successful save, a creature takes half the initial damage and half the damage at the end of its next turn. At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the initial damage increases by 2d6 for each slot level above 4th.