Wave of Lightnings

You stretch your fingers and unleash a shocking wave of lightnings in a 20-foot cone. Each creature in the area must make a Constitution saving throw. On a failed save, a target takes 5d8 lightning damage,  and is paralyzed until the start of it's next turn. On a successful save, a target takes half as much damage and isn’t paralyzed.

Target with armor made of metal has disadvantage on saving throw.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d8 for each slot level above 3rd.