Macuahuitl of Revealing

Weapon (macuahuitl), very rare

You gain a +2 bonus to attack and damage rolls made with this magic weapon.

When you hit a shapechanger with this weapon, the shapechanger takes an extra 3d6 damage of the weapon type, and it must succeed on a DC 15 Constitution saving throw or revert to its original form. The shapechanger cannot assume a different form for one minute after it fails its Constitution saving throw. Legends claim the hero-gods used these weapons to unmask the emperor’s serpent-advisors.