When you attack using a great bow, you may declare that you are using one of these. If you succeed on your attack roll, the arrow does additional damage equal to your Wisdom bonus; moreover, your target’s next attack is made with disadvantage. At the end of the battle you can recover your used arrows if circumstances allow it, unless you rolled a 1, in which case, that arrow is lost or broken beyond recovery.
For many long centuries, the “Men of the Sea” sent cohorts of archers to deluge their enemies under a rain of steel. Their long, black-feathered arrows can still be discovered inside burial mounds, among the tall grass of Eriador or where long-forgotten battles were fought across Gondor.