Electrocute

You attempt to touch the target and deliver a fatal shock. Make a melee spell attack against the target. On a hit, the target takes 3d12 lightning damage and must make a Constitution saving throw or be Stunned until the end of your next turn. A creature wearing metal armor has disadvantage on this save.

At higher levels. When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 1d12 for each slot level above 2nd.