You channel destructive energy through your touch. Make a melee spell attack against a creature within your reach. The target takes 8d10 necrotic damage and must succeed on a Constitution saving throw or have disadvantage on attack rolls, saving throws, and ability checks for a number of rounds equal to the spell slot you expended. An affected creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. This spell has no effect on constructs or undead.