Source: Dungeon Master's Guide

Weapon (Any Ammunition), Very Rare

This magic ammunition is meant to slay creatures of a particular type, which the DM chooses or determines randomly by rolling on the table below. If a creature of that type takes damage from the ammunition, the creature makes a DC 17 Constitution saving throw, taking an extra 6d10 Force damage on a failed save or half as much extra damage on a successful one.

After dealing its extra damage to a creature, the ammunition becomes nonmagical.

1d100 Creature Type
01-10 Aberrations
11-15 Beasts
16-20 Celestials
21-25 Constructs
26–35 Dragons
36–45 Elementals
46–50 Humanoids
51–60 Fey
61–70 Fiends
71–75 Giants
76–80 Monstrosities
81–85 Oozes
86–90 Plants
91–00 Undead