Cardiomyopathy

You stop the heart of a living creature you touch. That creature must make a Constitution saving throw. On a successful save, it takes 5d10 necrotic damage and has its speed reduced by 10 feet for one minute. On a failed save, the target takes 8d10 necrotic damage and is incapacitated. The target must then repeat the saving throw at the end of each of its turns with disadvantage, ending the effect on a success, but taking 2d10 more damage on a failure.