Arrow of slaying

Arrows of slaying were magically enchanted arrows designed to kill one particular type of target.

Description
Several different types of arrows of slaying existed, meant for a wide variety of targets, with varying degrees of specificity. For example, while very specific arrows of blue dragon slaying existed, it was also common to find more vague arrows of dragon slaying.

Other, less common variants of this type of projectile existed, such as bolts of slaying, intended to be used in crossbows.

Powers
When an arrow of slaying hit its intended target, it caused a devastating amount of damage, some of which could be resisted by the target. After one hit, the enchantment ended and the arrow of slaying became an ordinary arrow.

Notable Arrows of Slaying
During the council of metallic dragons led by Protanther in the Nether Mountains in the late 15 century DR, a few members of the council considered awarding arrows of dragon slaying to adventurers in their quest to prevent the return of Tiamat at the hands of the reformed Cult of the Dragon.