Long Fang of the Moon

You gain a +3 bonus to attack and damage rolls made with this silvered longsword. 

Weapon attacks using long fang of the moon deal an extra 2d6 radiant damage against creatures. When you hit a shapeshifter with this weapon, it makes a DC 30 Constitution saving throw or reverts to its original form. If it fails this saving throw, you may choose to prevent the shapeshifter from transforming for up to 10 minutes.