Blitzhausen

You imbue a tiny metal object with a spark of lightning. Whenever a creature attempts to hold this item, it must make a Constitution save against your spell save DC. If the creature fails this save, they suffer 1d4 lightning damage and cannot drop the object, on a successful save they suffer half the damage and must drop the object. This damage, and the save, repeat every round in which the object is being held or worn by the creature, unless the object is entirely contained within a substance electricity cannot penetrate, such as stone, wood, glass, or clay, but not leather. The creature who cast this spell, and any number of creatures specifically named by the caster, are immune to this effect. If the affected object is a melee weapon or is used as an improvised weapon, the weapon deals an extra 1 lightning damage on a hit.

When cast at higher levels, this spell deals an extra 1d4 lightning damage per round when held or carried for every level above the first, and an extra 1 lightning damage on a hit when used as a weapon.