Wither

You unleash a pulse of necrotic aether at a creature within range. The target must succeed make a CON saving throw or take 3d6 necrotic damage and have its movement speed halved and any healing received negated until the end of its next turn; on a successful save, the target still takes half damage, but suffers no speed or healing penalty.

At Higher Levels: When this spell is cast using a 3rd level spell slot or higher, it deals an additional 2d6 necrotic damage for each level above 2nd.