Electro Glyph

Using your bonus action, you magically inscribe a mystic pictogram of lightning on the item used in the casting of this spell. When the object hits a creature it deals an additional 1d4 lightning damage. Also, at any time, you may use your reaction to cause the glyph to explode. Each creature within 10 feet must make a dexterity saving throw. On a failed save creatures in the impact radius take 2d8 lightning damage, and half on a successful save. 

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the lightning damage increases by 1d8 for each slot level above 1st.