2024 rules reference for Ammunition of Slaying.
Weapon (Any Ammunition)
This magic ammunition is meant to slay creatures of a particular type, which the GM 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 1d100 Creature Type 01-10 Aberrations 51-60 Fey 11-15 Beasts 61-70 Fiends 16-20 Celestials 71-75 Giants 21-25 Constructs 76-80 Monstrosities 26-35 Dragons 81-85 Oozes 36-45 Elementals 86-90 Plants 46-50 Humanoids 91-00 Undead