Cascading Devastation

Crippling necrotic decay affects the target, augmenting the spell with their life force then attempting to spread from them.

Choose a creature within range. The target must make a Constitution saving throw. On a failure, they take 2d10 necrotic damage and you may choose a new target within 10 feet of the previous target to make a new saving throw, repeating this effect on a new target for each successive failure and increasing the damage by 1d10 each time. On a success, a target takes half damage and the effect stops spreading. A creature can be affected by this spell more than once, but halves any damage taken after their first failure.