Acid Long Bow

This is a +1 long bow, made of black wood and carved with swirling patterns. Once per day it can cast Melf's Acid Arrow on the next arrow fired. The arrow does its normal damage plus 4d4 acid damage immediately and 2d4 acid damage at the end of its next turn. On a miss, the arrow splashes the target with acid for half as much of the initial damage and no damage at the end of its next turn.