Tesla Dome

Electric sparks flow around your body and your hair becomes statically charged. Electric bolts erupt from your body hitting every metal object near you.

For the duration of this spell each creature that enters a 20 foot sphere radius centered around the caster or starts its turn there and is carrying a metal object with it has to make a Constitution saving throw. It takes 3d6 lightning damage and is knocked prone on a failed save, or half as much damage and isn't knocked prone on a successfull one.
If a prone creature fails this saving throw it becomes paralysed until the spell ends.