Break a Leg

A shimmering coil of arcane power disrupts the target and steals their luck. It’s yours if you want it. The target must make a Charisma saving throw. On a failure, the target takes 4d6 bludgeoning damage. On its turn, the first d20 it rolls, you may steal. The target rerolls, and you may use the stolen result for your next d20 roll. On each turn, the effect, ignoring the damage, repeats, although you may never have more than one stolen result at a time. On a successful saving throw, the creature takes 4d6 bludgeoning damage, and you may steal the next d20 it rolls and use it, the spell then ends.