Arcane Bow of Piercing

    The caster summons an arcane bow into his/her hand that deals 1d8+ your spellcasting modifier piercing damage on a hit. The shot from the bow will go through the original target, and deal half of its total damage to any one thing behind it (Rounded up). Example: A wizard shoots an arrow for 7 damage, plus his ranged spellcasting bonus damage to equal twelve damage. He kills the goblin he's shooting at, and deals another six damage to the goblin behind it, killing it as well. 

Note- Any object struck with a shot from this bow will have a hole drilled into it where the shot struck