Electro Bolt

You create three bolts of pure electricity and hurl them at targets within range. A creature can be targeted only once by each casting of this spell.

Make a ranged spell attack for each bolt. On a hit, the target takes 4d10 lightning damage. You have advantage on the attack roll if the target is wearing armor made of metal.

You can delay the release of the bolts in order to increase their power. At the end of your turn, if the bolts have not yet been hurled, the damage increases by 1d10 and you gain a +1 bonus to the attack roll of each bolt. When the spell ends, either because your concentration is broken or because you decide to end it the bolts are hurled towards their targets. 

If you target a creature made of inorganic material such as stone, crystal, or metal or a magically created structure or object (but not magical items) that isn't being worn or carried, the spell deals maximum damage to it.

If you target a nonmagical structure or object that isn't being worn or carried, the spell deals maximum damage to it and the damage is doubled.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, you create one additional ray for each slot level above 3rd.