Arrow of Expulsion (Patreon)

Weapon (arrow), rarity varies

The head of this magic arrow emits a concussive explosion in a 15-foot radius upon impact, centered on the target of the attack. Each creature within the explosion's area must make a Strength saving throw. The save DC for this effect and the amount of force damage that it deals are based on the arrow's rarity: uncommon (DC 13; 3d6), rare (DC 15; 6d6), or very rare (DC 16; 9d6). On a failed save, a creature takes the damage and is pushed up to 15 feet away from the point of impact, or away from you if it was the target of the attack. If a creature fails the saving throw by 5 or more, it's also knocked prone. On a successful save, a creature takes half as much damage and isn't pushed. The explosion's damage is doubled against structures and objects that aren't being worn or carried. Hit or miss, the arrow is then destroyed.

Other types of magic ammunition of this kind exist, such as bolts of expulsion meant for a crossbow, though arrows are most common.

On his first day of being the goblin king, Gruum stood once more, triumphantly, on the ledge from which he pushed his predecessor. However, Gruum couldn't have known that others had come with the same plan. With a faraway cry and the twang of a bow, he was suddenly filled with regret of becoming goblin king. As he fell to the same end as the king before him, he saw a new king stand atop the ledge.