Bigga's Ball of Lightning

After the contents are places inside the metal orb you start to pour some magic into the orb and lightning is channeled around the orb. Then you launch the round shaped lightning ball to the target and as it hits the target area there is a brief second of silence in the area then a large static reverberation . Everything in the area take 8d6 lightning damage and must make a dexterity save against your spell dc. On a failed save targets take full damage and are paralyzed or stunned (dm's discretion) for 1 round. On a save targets take half damage but are knocked prone. If targets are wielding any metal weapons or wearing armor containing metal they have disadvantage on the save. 

At higher levels damage goes up 1d8 per level. If cast at 9th level all creatures in the area of the spell have disadvantage regardless wielding metal weapons or armor.